Mathematics for IGCSE & O level - Proportion (Section 1 - No. 18)
The amount of simple interest earned, *I*, is directly proportional to the principal, *P*, the rate, *R*, and the time, *T*. Which of the following equations represents this relationship, where k is a constant?
I = kP/RT
I = kPRT
I = k(P+R+T)
I= k*P + R + T
Paliwanag
Direct proportionality means the variables are multiplied together. So, I = kPRT