Question

George is making 8 gallons of Tropical punch. He has already poured in 1 3/4 gallons of pineapple juice and 2 1/2 gallons of orange juice. The only other ingredient is 7-Up. How much 7-Up does George need in gallons?

Answer 1

George will have to add `3 3/4` gallons of 7-Up to bring the total to `8` gallons.

Explanation:

Add the gallons of juice that he has already used. Subtract that from `8` gallons.

`1 3/4 + 2 1/2`

Convert both mixed fractions to improper fractions. Multiply the denominator by the whole number, add the numerator, and place the result over the denominator.

`((4xx1+3))/4 + ((2xx2+1))/2`

Simplify.

`7/4 + 5/2`

When adding or subtracting fractions, they must have the same denominator. Multiply `5/2` by `2/2` to get an equivalent fraction with `4` as the denominator.

`7/4+5/2xx2/2`

Simplify.

`7/4+10/4`

`17/4`

George has already poured in `17/4` gallons of juice.

To determine how much 7-Up he needs to add, subtract `17/4` gallons from `8` gallons.

`8-17/4`

Any whole number is understood to have a denominator of `1`. `(n=n/1)`

Rewrite the expression.

`8/1-17/4`

Multiply `8/1` by `4/4` to get an equivalent fraction with `4` as the denominator.

`8/1xx4/4-17/4`

Simplify.

`32/4-17/4`

`15/4`

Convert `15/4` to a mixed number. Divide `15` by `4` to get a whole number quotient and a remainder. The whole number quotient is the whole number of the mixed number, the remainder is the numerator, and the divisor `(4)`, is the denominator.

`15-:4` `=` `3` `"R"` `3`

`15-:4=3 3/4`

George will have to add `3 3/4` gallons of 7-Up.