Question

the principal p is borrowed at a simple interest rate of par for a. Of time

Answer 1

We have the next information

P=Principal=$4000

r=rate=1.5%

t=15 months= 15/2=1.25 years

$A=P\mleft(1+rt\mright)$$A=4000(1+(0.015)(1.25))=4075$

For the interest

$I=A-P=4075-4000=75$

The interest is $75