Raymond B. answered • 04/23/21
Math, microeconomics or criminal justice
the numbers don't add up. The problems must have a typo in it.
37 total students but a maximum 31 students is a contradiction.
18+5+8 = 31. If there's any overlap with some students taking both chemistry and math, then there's even less than 31 total. The 3 choices exhaust the possibilities. Either you take math, take chemistry or you don't take either.
Maybe the 5 was supposed to a 15? then it sums to 41, which means 41-37= 4 students are taking both chemistry and math, leaving 15-4 = 11 who take chemistry but not math. A Venn diagram could be useful.
Mathematically, the problem as is, would mean 31-37 =-6 students took both chemistry and math. Then 5-6 = -1 student took chemistry but not math. At one time, long ago, in the history of math negative number were not considered real. But even though they are real today, a negative person doesn't seem to have any real application. There is a math joke about that though. A biologist, physicist and mathematician are sitting at an outdoor cafe watching an abandoned building across the street. It's completely empty, then 3 people go in, Later 2 come out. the building is now totally empty again. the physicist explains it as a a discontinuity in space time, a worm hole into another dimension. The biologist disagrees and argues the 2 must have eaten the 3rd person. The mathematicians just laughs and says that's ridiculous, what explains it all is there originally was -1 person in the store. 3 + (-1) = 2.
Or another alternative. Maybe the problems really reads 18 took only math, 5 took only chemistry. 8 took neither, then there's the 4th category 37-31 = 6 who took both chemistry and math. Then 5 took chemistry but not math. But that's a trick question which requires no calculations. It's worse than asking who's buried in Grant's tomb. some police officers ask that to DUI suspects. Then use it as an excuse to arrest you, if you don't answer Grant.
