Question

Reese deposited $7500 for two years into a money market account. At the end of two years she had a total of $8700. What rate of interest did she receive? 
can you please give me explanation

Answer 1

She deposited $7500. So it is the principal.
At the end of  years, she had total of $8700. 
So the total amount is $8700 and the time period is 2 years.
Interest = Total amount - principal = $8700 - $7500 = $1200
We need the rate of interest.

we know that Interest = PTR/100
⇒1200 = 7500*2*R/100
⇒R = 1200*100/7500*2
⇒R = 120000/15000 = 8%

Rate of interest is 8%

Answer 2

PRINCIPLE = $7500
amount = $ 8700
simple interest = $ 8700 - $ 7500
= $ 1200
time  = 2 years
rate = (simple interest ×100)÷(principle × time)
= (1200×100)÷(7500×2)
= 8%