Question

Juan's gas tank is 1/4 full. After he buys 9 gallons of gas, it is 5/8 full. How many gallons can Juan's tank hold?

Answer 1

x = full tank

1/4x + 9 = 5/8x
1/4x - 5/8x = - 9
2/8x - 5/8x = -9
-3/8x = -9
x = -9 /(-3/8)
x = -9 * -8/3
x = 72/3
x = 24 gallons for a full tank <==

Answer 2

find change
1/4 to 5/8
make bottom numbe 8
1/4 times 2/2=2/8
2/8 to 5/8 is increase of 3/8
3/8 tank=increas=9gallons
3/8 tank=9 gallons
times both sides by 8/3
24/24 tank=72/3 gallons
1 tank=24 gallons

can hold 24 gallons