Question

Jennifer can clean her room in 2 hours, while John can clean the same room in 5 hours. How many hours would it take for them to clean the room together?

7
10
seven tenths
ten sevenths


I think the answer is tenth sevenths but im not sure! Please Help ASAP

Answer 1

Ten sevenths. Hope this helps

Answer 2

Answer: ten sevenths

Explanation:

Given: Time taken by Jennifer to clean her room
`t_1= 2 \text[ hours}`

Time taken by John to clean same room
`t_2= 5\text[ hours}`

If they work together to clean the room , then the total time taken by them is given by :-

`(1)/(t)=(1)/(t_1)+(1)/(t_2)\\\\\Rightarrow\ (1)/(t)=(1)/(2)+(1)/(5)\\\\\Rightarrow\ (1)/(t)=(5+2)/(10)\\\\\Rightarrow\ (1)/(t)=(7)/(10)\\\\\Rightarrow\ t=(10)/(7)\text{ hours}`