   SEARCH HOME Math Central Quandaries & Queries  Question from BARBARA, a student: The average weight 6 crates of cantaloupes is 61 lbs, if 3 of the crates weigh 72, 59, and 70 lbs. which of the following could be the weight in pounds of the other 3 crates? a. 49,59,60 b. 51,53,54 c. 53,57,58 d. 54,56,60 e. 57,57,57 I keep getting the wrong answer, spending to much time on this problem. Thank you We have two responses for you

Hi Barbara,

If the average weight of the 6 crates of cantaloupes is 61 pounds then

(total weight of the 6 crates)/6 = 61

Thus the total weight is 6 × 61 = 366 pounds. The three crates you know about have a total weight of

72 + 59 + 70 = 201 pounds.

366 - 201 = 165 pounds so the 3 remaining crates must have a total weight of 165 pounds. None of the five options given have a total weight of 165 pounds. The closest are a. and c. which each have a total of 168 pounds. My guess is that there is a typo somewhere in the problem.

Penny

Hi Barbara.

If the average weight is 61 lbs, then the total weight of the 6 crates is 366 lbs (6 x 61). The first three are 72+59+70 = 201 lbs. So the other three total 366-201 = 165 lbs. None of your choices has exactly 165 lbs, but if we assume that the average weight was rounded off ( within 1/2 lb) to 61 lb, then the total weight uncertainly is 6 x (1/2) = 3 lbs. So you are looking for a total that is between 162 and 167.99 lbs (168 lbs would round up).

You have two answers that add to 168, but none that fit the valid range. Perhaps there is a mistake in the question in your book or in what you typed in for us.

Stephen la Rocque     Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.