Improvement Flashcards
If someone says 12 min per km, what is the rate
1/12 km/min
If you have ‘men’ that work at x rate and ‘boys’ taht work at y rate; and you have 8 men and 6 boys, you could also convert all “men” to “boy” units so that stops mattering
:)
The price of the most expensive book is less than $17. if a min max problem, what would be the test case you’d use?
$16.99. Prices don’t have to be integers!!!
If I tell you the following, how do you express it mathematically? The number of stamps that Kaye and Alberto had were in the ration of 5:3 respectively. After Kaye gave Alberto 10 of her stamps, the ration of the number of Kaye had to the number of Alberto had was 7:5. As a result of the gift, Kaye had how many more stamps than Alberto
(5x-10)/(3y+10)=7/5
What’s 8/99? 10/99? 15/99?
- 080808
- 101010
- 151515
- 0555
0. 000432432
5/90
432/999000
What are the rules of a terminating decimal?
Denominator of a REDUCED fraction can be re-written as 2^n * 5^m. For example, 250 can be: 2*125 (checks the box)
|s|< 5, how do you solve for this?
-5 < s < 5
When is |x-4| = 4-x
when x<0, then |x| = -x. For example, |-3|=3, you flip sign. So in this case, because sign is flip, must be that x-4<=0, or x<=4
what is sqrt (x^2) in modulus?
|x|
What is |x| if x<0?
-x
Sum of arithmetic series formula
Sum = n (a1 + an)/2
Sum of geometric series
Sum = a1 (1-r^n)/(1-r)
Remember that when you have a partial prime box, basically the answer is “is it divisible by 12” is
sometimes yes / sometimes no
If you’re in the number line and R is left to 0, and S right to 0, but the prblem tells you, using the absolute values, what is the average
Then r and s becomes positive so you need to add the (-) side to r: (-r+s)/2