Question

Perfume is sold in two different sizes of bottle. The 80ml bottle is priced at £55. The 50ml bottle is usually priced at £45, but is on special offer. If you buy one 50ml bottle of perfume you can get a second for half price.
By calculating the price per ml determine which offers the best value for money the 80ml or two 50ml bottles ? You must show your working .

Answer 1

1ml of 80ml bottle: 55/80 = 0.6875 pence

1ml of 50ml bottle: 45/50 = 0.9 pence

If no special offer the first bottle is a better value for money.

Since special offer though, you'd be buying;

50ml bottle £45 + another 50ml £22.5 = £67.5 in

which case 1ml would cost;

67.5/100 = 0.675 pence. Hence buying 2x50ml

bottle would be a better value.