Missed Quant Flashcards
A farm has chickens, cows and sheep. There are three times the number of chickens and cows than sheep. If there are more cows than chickens or sheep, and together, cows and chickens have a total of 100 feet and heads, how many sheep live at the farm?
A. 5 B. 8 C. 10 D. 14 E. 17
Before approaching this question. We should invest 15 seconds to think about the best approach.
We are told that cows and chicken have 100 feet and heads total.
Chicken= 3 heads and feet Cows= 5 heads and feet
We are also told that chicken+cows=3sheep
We know that chicken has to be multiple of 5’s and chickens are less than cows. So our options could be be 5 chicken, 17 cows, or 10 chickens and 14 cows. we know that the number of sheep must be divisible by 3, so it must be that there are 10 chickens and 14 cows. this means that there are 8 sheep.
If all of the six faces of a concrete block are rectangular, what is the volume of the block?
(1) Each of the four lateral faces of the block has an area of 200 square inches.
(2) The top of the block is square and has an area of 400 square inches.
to figure out this problem, we must realize that to find the volume of a cube/rectangle, we need to know lengthwidthheight.
1) there are many options can result in each lateral face having 200sq^in. for example 2010 or 405.. furthermore, we don’t know the top portion of the surface.
2) the top is a square with an area of 400, this means that each side is 20*20. however, we don’t know the dimensions of the four sides of the figure.
When combining both answer choices, we can see that the dimensions have to be 202010 because the area of the sides have to be 200. We know that the top is 20 by 20. So to plug in the number, the know the other length must be 10.
As such, the answer choice is C.
If a and b are integers, is a + b + 3 an odd integer?
(1) ab is an odd integer.
(2) a − b is an even integer.
Remember for this question, we need to understand that odd+odd=even, even+even=even, and odd+even=odd
(1) this means that a & b are both odd integers, because if one value was even then the whole value would be an even integer. this answer choice is S.
(2) a-b is an even integer
this means that 4-2=even
or 3-1=2 even
Let’s check our answer choices 4+2+3=9, odd
3+1+3=7 odd. Thus, this is S
Answer choice is D
Last year, a certain company began producing soup A and sold all of the soup A that it produced. To make all of the soup A produced last year, raw ingredients were cooked until their weight was 30% less than their original weight, then a total of 28 kilograms of herbs and spices were added just before soup A was packaged in cans. Did the company sell more than 4,800 cans of soup A last year?
(1) Each can of soup A sold last year contained 0.45 kilograms.
(2) Last year, the total weight of the raw ingredients for soup A, before cooking and excluding the herbs and spices added after cooking, was greater than 3,000 kilograms.
I orignally picked answer C.
We want to know if the company sold more than 4,800 cans of soup A last year. For that we would need to know
1) capacity of each can
2) weight of all raw ingredients
from the information provided, we can set up an equation .7x+28 = final weight of can
1) tells us the capacity, but does not tell us the weight that goes into each can. NS, eliminate A&D
2) this says that x>3,000. Let ‘s plug this into our equation. 3000*.7=2100
2100+28=2128 KG, but we don’t know the capacity of each can. Eliminate
(1)+(2) we know that each can of soupd is .45kg, so
4800*.45 (or 9/20) = 2,160.
As (2) says that it can be be >2,160 or <2,160, the answer is E.
At a restaurant, a group of friends ordered four main dishes and three side dishes at a total cost of $91. The prices of the seven items, in dollars, were all different integers, and every main dish cost more than every side dish. What was the price, in dollars, of the most expensive side dish?
(1) the most expensive main dish cost $16
(2) the lease expensive side dish cost $10
I was baited into choosing answer C
(1) we can see that this is S. The only possible outcome is noted below
16+15+14+13+12+11+10=91
(2) same as the statement above. the only outcome is
16+15+14+13+12+11+10=91.
As such, the answer is D.
If an ≠ 0 and n is a positive integer, is n odd?
(1) a^n + a^(n + 1) < 0
(2) a is an integer
this is difficult problem, i choose answer choice E
(1) if factor out this problem, we get a^n(1+a)<0.
looking at the two sets, we know that the two things being multiplied must have opposite signs.
if n=even then the left is positive and -1<a></a>
A palindrome is a number that reads the same forward and backward, such as 121. How many odd, 4-digit numbers are palindromes?
A. 40 B. 45 C. 50 D. 90 E. 2500
remember to read the quesiton carefully as it asks for ODD numbers only.
_ _ _ _
If we are only considering odd numbers, then the last blank space up there would only have 5 possibilities (1,3,5,7,9). Furthemore, the first blank would have to equal the last blank to be considered a palindrome.
Next, the two middle blanks can be any single digit, so we have 10 options. We know that they two inner blanks must match each other as well.
Piecing together the logic, we have 5101*1, because we have 5 digits to choose from for the first blank and we have 10 digits to chose from for the second blank. Thus, the answer is C, 50.
If a and b are positive integers, what is the remainder when ab is divided by 40?
(1) b is 60% greater than a.
(2) Each of a^2b and ab^2 is divisible by 40.
I got this question incorrect, because I was indimindate by the problem.
(1) states that B=8/5(A).
We can further simplify this if we see 5B=8A
From (1), we can see that A must be a multiple of 5 and B must be a multiple of 8. Therefore, ab will always produce a remainder of 0.
(2) NS, plug in numbers to see.
Which of the following integers is NOT a divisor of x if x = (21)(3^7) – (112)?
A 7 B 11 C 15 D 17 E 35
I approached this problem correctly, as I broke down the numbers into their prime factorization.
x=(73)(3^7)-(2^47)
We can start by factoring out the 7
7((3^8-2^4)), we can expanding by seeing a difference of two squares
7(3^4+2^2)(3^4-2^2), we can further expand and we can see that we eventually get
{7857*11}
We can get all factors in the options except for 17.
In a room filled with 7 people, 4 people have exactly 1 sibling in the room and 3 people have exactly 2 siblings in the room. If two individuals are selected from the room at random, what is the probability that those two individuals are NOT siblings?
A. 5/21 B. 3/7 C. 4/7 D. 5/7 E. 16/21
{A,B,C,D,E,F,G} ===> represents the people in the room
with the information from the passage, we can see that
4 people in the room has one sibling, we can assume that
{A,B} and {C,D} are a sibling pair.
3 people have exactly 2 siblings in the room
{EF}, {EG}, and {GF} are a sibling pair noted above.
We can see that 7 choose 2, there are 21 possibles ways to choose from the group.
the probability that any 2 individuals in the group are NOT siblings are 1-5/21=16/21.
In a group of 68 students, each student is registered for at least one of three classes – History, Math and English. Twenty-five students are registered for History, twenty-five students are registered for Math, and thirty-four students are registered for English. If only three students are registered for all three classes, how many students are registered for exactly two classes?
A. 13 B. 10 C. 9 D. 8 E. 7
three venn diagram equation is
sum of students = sum of A+sum of B+sum of C-people in both - 2(people doing all 3)
68=25+25+34-2(3)-x
x=10
What is the distance between x and y on the number line?
(1) |x| – |y| = 5
(2) |x| + |y| = 11
(1) we can plug in actual values to test
assume that x=6 and y=1 abs value equals 5
however, x=6 and y=-1, means that the abs value distance is 7. NS
(2) plug in numbers, assume x=5 and y=6 equals 11.
however, x=5 and y=-6 results in different absolute value results.
combined there are still not sufficient.
A rectangular wall is covered entirely with two kinds of decorative tiles: regular and jumbo. 1/3 of the tiles are jumbo tiles, which have a length three times that of regular tiles and have the same ratio of length to width as the regular tiles. If regular tiles cover 80 square feet of the wall, and no tiles overlap, what is the area of the entire wall?
A. 160 B. 240 C. 360 D. 440 E. 560
Alternatively, use a neat shortcut. If 1/3 of the tiles are jumbo, then 2/3 are regular. In that case, for every two regular tiles, there is one jumbo tile. One jumbo tile has an area 9Lw and two normal tiles have an area 2Lw, so the tiles will be placed in “sets” of 9Lw + 2Lw = 11Lw. The correct answer, then, must be a multiple of 11, and only answer (D) is a multiple of 11.
Bob just filled his car’s gas tank with 20 gallons of gasohol, a mixture consisting of 5% ethanol and 95% gasoline. If his car runs best on a mixture consisting of 10% ethanol and 90% gasoline, how many gallons of ethanol must he add into the gas tank for his car to achieve optimum performance?
A. 9/10 B. 1 C. 10/9 D. 20/19 E. 2
We know that that there is currently
1 gallon E
19 gallon G in his tank right now.
Since we want E=10%, we can set up an equation
(1+x)/(20+x)=1/10, if we solve then we can get the correct answer
C.
If 8x > 4 + 6x, what is the value of the integer x?
(1) 6 – 5x > -13
(2) 3 – 2x < -x + 4 < 7.2 – 2x
Remember that x must be an integer
from the stem we get x>2
(1) we can solve and we get x<19/5
this is sufficient, we can conclude that x=3
(2) = we can break this into two inequalities
3 – 2x < –x + 4
3 – 4 < x
–1 < x
–x + 4 < 7.2 – 2x
x < 7.2 – 4
x < 3.2
So, we end up with –1 < x < 3.2. Since we know from the information given in the question that x > 2, we can conclude that 2 < x < 3.2. The only integer between 2 and 3.2 is 3. Therefore, x = 3.
If x is a positive integer and 4x–3=y4x–3=y, which of the following CANNOT be a value of y ?
A. 1
B. 7
C. 13
D. 61
E. 253
B
If p, r, and s are consecutive integers in ascending order and x is the average (arithmetic mean) of the three integers, what is the value of x ?
(1) Twice x is equal to the sum of p, r, and s.
(2) The sum of p, r, and s is zero.
I originally seletcted as my answer because I did not understand (1).
However, we can see that since p,r,s are consecutive integers then it must be true that
r=x… the median = mean.
Furthermore, we can see that 2x=(x-1)+(x)+(x+1), simpfiy and we get 2x=3x.. the only answer that would satisfy that is 0. thus S.
Answer is D.
The total price of 5 pounds of regular coffee and 3 pounds of decaffeinated coffee was $21.50. What was the price of the 5 pounds of regular coffee?
(1) If the price of the 5 pounds of regular coffee had been reduced 10 percent and the price of the 3 pounds of decaffeinated coffee had been reduced 20 percent, the total price would have been $18.45.
(2) T he price of the 5 pounds of regular coffee was $3.50 more than the price of the 3 pounds of decaffeinated coffee.
I orginally picked ans B.
the answer should be D, because option (1) presents us with new information which we can use to solve the problem