1MA0 Foundation June 2015 Paper 2 Q17

17 Buttons are sold in packets and in boxes.

There are 6 buttons in a packet.
There are 15 buttons in a box.

Nomusa buys \(d\) packets of buttons and \(f\) boxes of buttons.
She buys a total of \(T\) buttons.

Write a formula for \(T\) in terms of \(d\) and \(f\). (3)