Word Problems Flashcards
How to solve for age problems?
Step 1: define variables for the present day
Step 2: represent each age in the future of the past
Step 3: organize the info from the previous steps into a matrix, with columns representing the present, past or future and the rows representing people or objects
Step 4: use the info in the matrix as well as from the problem stem to create equations and then use those to determine the answer
Price per item. What is the price per item when identical items are purchased?
The total cost paid over the number of items purchased
How is wage defined?
Wage = total amount paid / total amount of time worked
How to equate two different wages by using addition and subtraction?
When two people earn $n each, and $x is transferred from person A to person B to equalize their hourky wages, the formula is:
(n-x)/hours person A = (n+x)/hours person B
What is simple interest?
The interest one earns (or pays) is simply based on the original amount of principal borrowed or lent.
What is compound interest?
Occurs when interest earned (or paid) builds not only on the principal amount borrowed or lent, but also on any new interest that accumulates.
What is the equation for simple interest?
Principal x rate x time.
Remember that the e of both the rate and time must be the same.
When compound interest is calculated, the interest earned in each period is added to the principal and the interest earned in previous periods. These steps are followed until all interest has been calculated for all interest periods.
What is the compound interest formula?
A = P (1+ (r/n))^(nt)
A = is the future value
P = initial value (principal)
r = thr annual interest rate
t = time (in years)
n = is the number of compounding periods per year
What is the linear growth formula?
Fn = kn + p
Where,
Fn is the final value after the growth has occurred
K is the growth constant,
N is the number of growth periods,
P is the original value prior to growth
What is the formula for exponential growth problems?
V x N^t
Where V us the initial value
N is the growth factor
T is the number of periods
How can we breakdown a dry mixture problem?
1) the components of the mixture
2) the units of each component
3) the quantity of each component
What are you asked to do in a dry mixture problem?
We are asked to combine two or more “pure” dry components to create a final mixture
What components should you consider when looking at a wet mixture problem?
1) the components of the mixture
2)the concentration of the mixture
3) the quantity if each component
