We will solve this problems using proportions. One proportion will always be the percent proportion.

The other proportion will have the "is" number in the numerator and the "of" number in the denominator. Since the "is" number is what we are looking for we represent it by the variable N.
To solve the proportion we cross multiply…

15% of the members of the football team play both offense and defense. The Spartans have 60 players on their squad.

The first proportion we use is 20% over 100%. The other proportion will have the "is" number in the numerator and the "of" number in the denominator. Since the "of" number is we what we are looking for, we represent this by the variable N.
To solve the proportion we cross multiply…
20 x N = 90 x 100
20N = 9000
N = 450
Therefore the number we are looking for is 450.

  writer:Kevin Gallagher