Among four cars, weight of C1 is twice the weight of C2. Weight of C3 is half of the weight of C2. C4 is 40 kg heavier than C2, but 40 kg lighter thanC1. What is the weight (in kg) of C4?
The simple interest on a sum of money is 16/25 of the principal. The number of years is equal to the rate of interest per annum. What is the rate (in percentage) of interest per annum?