64 oz $14.08, because you get more for a smaller price
The answer is £140
First you find 20% of 1200 (which is basically 20 times 12) which gives you £240.
You add £240 to £1200 which is £1440
Then you take £300 off £1440 since he already paid the deposit.
That leaves you with £1140
1140 divided by 10 is 114