Question

Your dad put $1,000 into a new bank account to save money for a family trip. He earned $18.75 in simple interest after 15 months. What is the annual interest rate? Use the formula: I = Prt.

Answer 1

Step one multiply
15 x 1,000

Step two divide
15000/18.75=?

Answer 2

I=PRT
T=time in hears
P=principal=amount you put
R=rate

so 15 momths=15/12=1.25 years
prinicipa 1000
interset=18.75
subsitute
18.75=1000 times R times 1.25
multiply
18.75=R times 1250
divide both sides by 1250
0.015=R
R=rate in percent
percent means parts ot of 100
0.015/1 times 100/100=1.5/100=1.5%

so annual interest rate=1.5%