2/8 of an hour is 15,and 2/6 of an hour is 20 minutes. 20-15 is 5 minutes
Simply divide your wire by 12 and cut off the excess (as it cannot make a full 12-inch section).
27

÷12=2

So you have two 12-inch sections and an additional 3.4-inch section.
5% of £42 = £2.10
10% of £42 = £4.20
15% of £42 = £6.30
£42 - £6.30 = £35.70
£50 - £35.70 = £14.30
the answer is £14.30