How many 4-person groups can be selected from 12 people

The box plots show the average speeds, in miles per hour, for the race cars in two different races. which correctly describes the consistency of the speeds of the cars in the two races?

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?

Ateam of runners is needed to run a 1 2 -mile relay race. if each runner must run 1 4 mile, how many runners will be needed?