Edward C. answered 03/16/15
Tutor
5.0
(438)
Caltech Grad for math tutoring: Algebra through Calculus
Let F = number of times he goes on the Ferris wheel
Let D = number of times he goes on the dizzy cups
He goes on the ferris wheel 4 times more than the dizzy cups ==> F = D + 4
He uses 30 tickets ==> 4*F + 3*D = 30
Substitute the value for F from the 1st equation into the 2nd equation
4*(D + 4) + 3*D = 30
4*D + 16 + 3*D = 30
7*D = 14
D = 2
So F = 2 + 4 = 6
He went on the Ferris wheel 6 times and the dizzy cups 2 times
Check: 6 - 2 = 4 times more on Ferris wheel than dizzy cups
4*(6) + 3*(2) = 24 + 6 = 30 tickets used