HELP 9th Grade Algebra ll Word Problem

Question

QSR, Quality Service Research, Magazine studied drive-through times for fast food restaurants and Wendy's had the best time, with a mean time spent in the drive-through of 138.5 seconds. Assume drive-through times are normally distributed with a standard deviation of 29 seconds. If 220 vehicles use the drive-through at Wendy's on a given day, approximately how many vehicles will get through Wendy's drive-through in less than 100 seconds?

A. 20     B. 67      C. 153     D. 200

Answer 1

Well; this makes more than 3 st. deviations. That is, the area under normal distribution curve in this limit is almost 100% (99.95%) which corresponds to answer D., closest to 100% to 220 out of all possible choices ...