Equations and inequalities

Question

Sam's gas tank Is 3/10 full. After he buys 11 gallons of gas it is for 4/5 full how many gallons Can Sam's tank

Answer 1

3/10 full + 11 gallons = 4/5 full

3/10 F + 11 = 8/10 F

(8-3)/10 F = 11

5/10 F = 11

1/2 F = 11

F =2(11)

F = 22 gallon tank

3/10 of 22 = 66/10 = 6.6 g.

6.6 g. + 11 g. = 17.6

17.6 = 4/5 of 22 = 88/5 = 17.6