10 - 2x = 120
120 + 10 = 130
130 / 2 = 65
x = 65
2(65) - 10 = 120
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.
Answer:
28%
Step-by-step explanation:
The new square has length: 10 + l, where l is the original length of the square, and it's area is (10 + l)^2;
So, we solve the equation: 3 x l^2 = (10 + l)^2;
Then, 3 x l^2 = 100 + 20 x l + l^2;
Finally, 2xl^2 - 20xl - 100 = 0; / ÷2;
l^2 - 10l - 50 = 0 (we use the quadratic equation formula);
The only positive solution is l = 5(1+ \sqrt{3} );
