A roller coaster has 3 trains with 8 rows per train. Riders stand in rows of 4, for a total of 32 rider per train. The operators of the coaster recorded the number of riders on each train during a run. On the first train, the operators reported that 7 1/4 rows were filled. On the second train, all 8 rows were filled, and on the third train, 5 1/2 rows were filled.
How many rows were empty on the first train? How many additional rider would it take to fill the empty rows? Explain your answer.
8 - 7.25 = ?
4 * ? = ??
After calculating, you do the explanation.