Question

Help!!! urgent !!

robert can paint a fence in 6 hours. robert and juan together can paint a fence in 3 hours.

what equation can represent the number of hours, x, juan can paint the fence by himself?

Answer 1

x = 1 / (1/3 - R)

Explanation:

Let's call Robert R, and Juan J.

6R = 1 (think of 1 as 100% of the job done). call 6R = 1 equation '1'.

xJ = 1, J = 1/x (call this equation '2').

if Robert and Juan can do it together in 3 hours, then:

3(R + J) = 1

3R + 3J = 1

3J = 1 - 3R

J = 1/3 - R

1/x = 1/3 - R

x = 1 / (1/3 - R)