#7. If Christiano paid a total of 103.35 for 13 pairs of underpants, each pair of underpants would have cost him/her 7.95 each. 103.35/13=7.95. Since Carlos only bought 7, he paid a total of 55.65. 7x7.95=55.65
#8. If the cost of 4 kg of broccoli is 5.52, but you only buy 3 kg, take 4/3 = 5.52/x and solve for x. 4/3=1.333 (repeating) 1.33 = 5.52/x. 1.33x=5.52. x=4.14. This means that the cost of 3 kg of broccoli was 4.14. Since the total cost of the trip was 5.69, you take 5.69-4.14=1.55. Therefore, 2.5 kg of carrots cost 1.55. I am not sure the conversion to pence.