Lets x is the amount of money Paul spent
y is the amount of money John spent
Henry spent 3 times as much as paul = 3x
so
John and paul spent $45 altogether: x + y = 45
john and henty spent $65 altogether: 3x+y = 65
solve the equations
3x+y = 65
x + y = 45
---------------subtract
2x = 20
x = 10
x + y = 45
y = 45 - x
y = 45 - 10
y = 35
3x = 3(10) = 30
so
Paul spent $10 (x)
John spent $ 35 (y)
Henry spent $30 (3x)
answer: John spent $ 35
double check:
$ 35 + $ 10 = $45 (John and Paul spent $45 altogether)
$ 35 + $30 = $65 ( John and Henry spent $65 altogether)
