Multiple purchase discount calculator

Some products on Goodfellowpublishers.com attract a discount for multiple puchases. These are calculated in your shopping cart according to the quantity you're buying. The consequent unit price is also shown in your chosen currency. You can use this page to see the affect of bulk purchasing. On Goodfellowpublishers.com, products are subjected to a maximum discount of 50%

Quantity	Total	Unit
1	4.50	4.50
2	8.78	4.39
3	12.84	4.28
4	16.69	4.17
5	20.36	4.07
7	27.15	3.88
8	30.29	3.79
9	33.28	3.70
10	36.11	3.61
15	48.30	3.22
20	59.55	2.98
25	70.80	2.83
30	82.05	2.74
40	104.55	2.61
50	127.05	2.54
60	149.55	2.49
70	172.05	2.46
80	194.55	2.43
90	217.05	2.41
100	239.55	2.40
250	577.05	2.31
500	1139.55	2.28
750	1702.05	2.27
1000	2264.55	2.26