Foundation January 2020 Paper 2R Q17

17 Three tins, \(A\), \(B\) and \(C\), each contain buttons.

Tin \(A\) contains \(x\) buttons.
Tin \(B\) contains 4 times the number of buttons that tin \(A\) contains.
Tin \(C\) contains 7 fewer buttons than tin \(A\).

The total number of buttons in the three tins is 137

Work out the number of buttons in tin \(C\).

(4)