The monthly standing charge for a electrical company is €12.50 plus a cost of €0.16 per unit of electricity used.

Question

A customers monthly bill was €156.18. Determine how many units of electricity the customer used in that month.

Answer 1

I not sure but I think you do
156.18-12.50=
and then I think you divide the answer by 0.16

Answer 2

You're right.