Question

N a class there are less than 500 students . when it is divided by 3 it gives a whole number. similarly when it is divided by 4,5 or 7 gives a whole number. find the no. of students in the class

Answer 1

 you take 3 * 4 * 5 * 7, you will get 420
since that is less than 500, that's your number.
it's divisible by 3 or 4 or 5 or 7 because those are the factors that were used to make it up.