The IQR is the upper quartile-lower quartile. The way to determine this is finding the median of your numbers which is 53. Then you take the numbers higher than 53 and find the median of those which is 63.5. 63.5 is the upper quartile. Then you take the bottom half under 53 and find the median of those. The median of this is 53.5 53.5 is the lower quartile. Then just subtract 63.5-53.5 and you will get 10 as the IQR.
The answer is B, because you will have to multiple 42 by 7 to see how much money he will have in 7 weeks and then you will have to subtract 8 × 8.25 to see how much money he spent on his vacation.
