Question

kim can mow the greens at the golf course twice as fast as shayla can. Working together, they can mow the greens in 4 hours. How long does it take kim to mow the greens alone

Answer 1

Answer: Kim can mow the greens alone in 6 hours.

Step-by-step explanation:

Let K be the rate Kim mows the greens, and S the rate for Shayla.  The rates K and S will be in greens/hour.

We know they can mow 1 green in 4 hours.  We can state this as a sum of their rates times the 4 hours equals one green:

(4 hours)*(K + S) = 1 green

We are told that K = 2S [Kim is twice as fast as Shayla]

Subsititute:

(4 hours)*(K + S) = 1 green

(4 hours)*(2S + S) = 1 green

4*(2S + S) = 1 green

12S = 1 green

Shalya's rate is 1 green/12 hours

Kim is twice as fast:  K = 2S

Kim's rate is 1 green/6 hours.