The sum of the ages of will and Annette is 20. If will is 4 years older than Annette how old is he?

Let Annette be x.

Will is 4 years older = x + 4

Total = 20

x + x + 4 = 20

2x + 4 = 20

2x = 40 - 4

2x = 16

x = 16/2

x = 8

Annette = x = 8, Will = x + 4 = 8 + 4 = 12

Therefore Will is 12 years old.