£168
Explanation:
He usually gets paid £8/hr.
Which means for half an hour of work, he is paid £8(1/2)=£4
And for three quarters of an hour, his is paid £8(3/4)=£2(3)=£6
So for time and a half pay on Saturday, he'll be paid: £(8+4)/hr × (7 hrs) = 84
And for Sunday it'll come to:
£(8+6)/hr × (6 hrs) = £84
So all together Jarvis mad £(84+84) = £168 last weekend.