Answer:mr.Sinofsky used 2 tanks of gas altogether
Explanation:
Mr.Sinofsky used 5/8 of a tank of gas on a trip to visit relatives for the weekend.
He used another 1 half of a tank commuting to work the next week. Converting 1 1/2 tank of gas to improper fraction, it becomes 3/2 tanks of gas.
He then took another weekend trip and use 1/4 tank of gas. Therefore, the total number of tanks of gas that Mr.Sinofsky used would be
5/8 + 3/2 + 1/4 = (5 + 12 + 2)/8 = 19/8
= 2 tanks of gas