Question

How many positive integers less than 400 are multiples of 4, 6 and 10?

Answer 1

Answer:

Positive multiples of 4 less than 30 are P={4,8,12,16,20,24,28}

Positive multiples of 6 less than 30 are Q={6,12,18,24}

Intersection of P and Q will be

P∩Q={12,24}

Count of numbers is 2 in intersection of P and Q.