Word Problems Flashcards
What does ‘is’ mean?
=
What does ‘was’ mean?
=
What does ‘has been’ mean?
=
What does ‘more’ mean?
+
What does ‘years older’ mean?
+
What does ‘years younger’ mean?
-
What does ‘less’ mean?
-
What does ‘times’ mean?
x
What does ‘less than’ mean?
-
What does ‘fewer’ mean?
-
What does ‘as many’ mean?
x
What does ‘factor’ mean?
x
how to solve age problems
- define variables for the ages in the present day
- represent each age in the future or in the past
- Organize the information from steps 1 and 2 in a matrix, with the columns representing the present, past, or future ages and the rows representing people or objects.
4: Use the information in the matrix as well as the problem stem to create corresponding equations for the present and future or past, and then use those equations to determine the answer.
Difference between variable and fixed costs?
Variable costs increase as more product is sold, but fixed costs do not.
When a company has both fixed and variable costs, the profit equation can be expanded to
profit = revenue - [total fixed costs + total variable costs]
formula for when two people transfer money to each other to equalize hourly wages
When two people earn $n each and $x is transferred from person A to person B to equalize their hourly wages, the formula is:
n-x/person a’s hours = n+x/person b’s hours
Fraction questions to find remaining portion
If you are given fractions, minus the remaining fraction from the whole. after youve done that for all of the portions that were taken, times those all together to find total remaining.
Example: One Sunday morning, a man is leisurely sitting in a coffee shop about to enjoy his full cup of gourmet coffee. During his first hour in the coffee shop, he drinks 1/4 cup of his coffee. During his second hour, he drinks 2/3 of his remaining coffee. During his third hour, he drinks 3/5 of the remaining coffee. What fraction of his coffee remains after three hours?
hour 1: 1-1/4: 3/4
hour 2: 1-2/3: 1/3
hour 3: 1-3/5: 2/5
times: 3/4 * 1/3 * 2/5 = 6/60 = 1/10 of remaining after three hours
general formula for remaining portion
The store began with x cell phones. After selling 1/y of the x cell phones, the store had x - 1/y * x cell phones in stock. simplified, the formula is x(y-1)/y where x is the total stock and y is the portion removed
Compound interest formula
A = P(1 + r/n)^n*t
A= future value
P = initial value [principal]
r = annual interest rate [expressed in decimal form]
t = number of years. if months, put over /12
n = number of compounding periods per year