DRDO Multi tasking staff Model paper 2

Simple Interest (S.I.) = Principal Amount × Rate × Time/100
Let the Rate = r%
∴ S.I. for Y = (9000 × r × 3)/100 = Rs. 270 r
S.I. for Z = (1600 × r × 5)/100 = Rs. 80 r
Total S.I. = Rs. 350 r = Rs. 1050 (Given)
⇒ r = 3%