Question 888430
Volume of a cylinder = Pi {{{r^2}}} * h
Sold at Pi {{{3^2}}} * 8 = 72 Pi for £15 or 4.8 Pi per £
Bought at Pi {{{5^2}}} * 18 = 450 Pi for 50£ or 9 Pi per £
If she sells the whole cylinder's worth, she will sell 6 of the small cylinders with {{{1/4}}}'s worth left over.  That's 90£ of oil that she bought for 50£, or 40£ profit.
If you count the quarter of a cylinder left over, add another 3.75£.