The fraction of Randy's gas tank is full now = 2/5
Explanation:
Randy's full gas tank = 5/8
After driving, he used = 3/8
Therefore, the remaining gas in the tank= gas in full tank - used gas
The remaining gas = 5/8 - 3/8= 2/8
The fraction of gas tank full now = remaining gas / full gas
= (2/8) / (5/8)
= (2/8)*(8/5) = 2/5