Question

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.

Answer 1

In this question we have to find the effect of doubling principal, rate or time .

First we have to check the formula which is

$I = P rt$

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.