What effect on the boiling point is produced by: (a) a soluble non-volatile impurity, such as table salt- (b) an insoluble foreign substance, such as sand?

Mike and mitchell decide to have a foot race. they mark off a stretch of 100 yards, and recruit cindy to work the stopwatch. after running the race and looking at the results, cindy declared that mitchell was the fastest. so how did the boys times compare?