Question

Reggie can line a football field in 120 minutes. Rosalinda can line a football field in 80 minutes. If they work together, how many minutes does it take them to line a football field?

Answer 1

48 minutes

Explanation:

Reggie can line 1/120 of a football field in 1 minute while Rosalinda can line 1/80 of a football field in 1 minute.

Therefore adding the 2 fractions we get; that BOTH of them can line 1/120+1/80 of a field in 1 minute. 1/120+1/80=1/48.

1/48 of a field can be done in a minute, so it would take them 48 minutes to do 48/48 or 1 whole field.

Answer 2

48 minutes

Explanation:

Given that;

Rosalinda can line the football field in 80 minutes

Reggie can line the football field in 120 minutes

Lets assume that if they work together, they will take T minutes to line the football field

Hence;

Thus in 1 minute, Rosalina can line 1/80 of the field where as Reggie can line 1/120 of the field

`(1)/(T) =(1)/(120) +(1)/(80) \\\\(1)/(T) =(2+3)/(240)\\\\`

The sum of the two fractions will represent the size of the field that can be lined in 1 minute.

`(1)/(T) =(5)/(240) \\\\(1)/(T) =(1)/(48) \\T= 48`

The reciprocal of the sum of the two fractions will represent the time taken for both Rosalinda and Reggie to line the field.

Answer ; It will take them 48 minutes for them to line the football field