Answer :
Let x = times in the pool
Let y = times in the basketball courts
42=3x+5y
x+y=12
Therefore y = 12-x
Subsitute for y
42 = 3x + 5(12-x)
42 = 3x + 60 -5x
Subtract 60
-18 = -2x
9 = x
The person used the pool 9 times.
Let y = times in the basketball courts
42=3x+5y
x+y=12
Therefore y = 12-x
Subsitute for y
42 = 3x + 5(12-x)
42 = 3x + 60 -5x
Subtract 60
-18 = -2x
9 = x
The person used the pool 9 times.