If the principal, interest rate, or time in a simple interest problem is doubled, and the other two quantities remain constant, how does the simple interest amount change? Explain.
Choose the correct answer below.
A.
The simple interest amount is found by multiplying the principal and interest rate and dividing by time. So, if the principal or interest rate is doubled, the interest amount will be doubled. If the time is doubled, the interest amount will be halved.
B.
The simple interest amount is found by multiplying the principal and time and dividing by the interest rate. So, if the principal or time is doubled, the interest amount will be doubled. If the interest rate is doubled, the interest amount will be halved.
C.
The simple interest amount is found by multiplying the principal, interest rate, and time. So, if any one of these values is doubled, it will cause the interest amount to be doubled.
D.
The simple interest amount is found by multiplying the principal, interest rate, and time. So, if any one of these values is doubled, it will cause the interest amount to be quadrupled.

As we see that interest is the product of principal, rate and time. So if any of these three doubles, that is if any of these three is twice of the original value, the interest gets doubled.

SO the correct option is C.

Answer Link