Question

Reynaldo can clean the house in 6 hours by himself. When Reynaldo and Ruben work together, it takes 3.5 hours. How long would it take Ruben to clean the house by himself?

Answer 1

Answer: Ruben can clean the house in 8.4 hours.

Explanation:

Since we have given that

Number of hours Reynaldo can clean = 6 hours

Number of hours Reynaldo and Ruben can clean = 3.5 hours

Let the number of hours Ruben can clean be 'x'.

Work done by Reynaldo is given by

`(1)/(6)`

Work done by both is given by

`(1)/(3.5)`

According to question, we get that

`(1)/(6)+(1)/(x)=(1)/(3.5)\\\\(x+6)/(6x)=(1)/(3.5)\\\\3.5(x+6)=6x\\\\3.5x+21=6x\\\\21=6x-3.5x\\\\21=2.5x\\\\x=(21)/(2.5)\\\\x=8.4`

Hence, Ruben can clean the house in 8.4 hours.