What is the smallest number with exactly 14 divisors?
Many numbers can be expressed as the sum of two or more consecutive integers. For example, 15=7+8 and 10=1+2+3+4. Can you say which numbers can be expressed in this way?
Do you know a quick way to check if a number is a multiple of two? How about three, four or six?
Let the number of Boys in Group 1 be x. The number of girls in Group 1 is therefore 40-x. and the number of girls in group 2 is 33 - (40 - x) = x - 7.
There are therefore 7 fewer girls in group 2 than boys in group 1.
This problem is taken from the UKMT Mathematical Challenges.