Hello!
First you have to find the area of the lawn
To do this you do l * w
22 * 31 = 682 square feet
Then you divide it by the amount of space one roll of AstroTurf covers
682/150 = 4.5
Since you can't by a half of a roll we round this up to 5
He will need 5 rolls of AstroTurf to cover the lawn
The answer is 5
Hope this helps!