Add (do not round): 10.6 + 6 + 2.09 =

Help please

Based on what i know about mean, this doesn't add up.

There are 20 children in the cast of a class play and 8 of the children are boys of the boys 4 have a speaking part in the play and of the girls 8 do not have a speaking part in the play if a child from the cast of the place chosen at random what is the probability that the child has a speaking part

36 inches/second = yards/minute how many yards?