first they ask how many statues does he make in a minute. they don't need anything about the # of ball one so just cross that out of your head. if he makes 42 in 168 min divide 168 by 42 to get that.
Now they ask how many balloons are used in one sculpture. since they are identical they all have the same amount. 252 balloons are used to have 42 sculptures. 252÷42 will get the # of balloons in just one.