SOLUTION: Dal and Kim can assemble a swing set in 1 1/2 hr. Working alone, it takes Kim 4 hr longer than Dal to assemble the swing set. How long would it take Dal, working alone, to assemble
Algebra ->
Polynomials-and-rational-expressions
-> SOLUTION: Dal and Kim can assemble a swing set in 1 1/2 hr. Working alone, it takes Kim 4 hr longer than Dal to assemble the swing set. How long would it take Dal, working alone, to assemble
Log On
Question 464388: Dal and Kim can assemble a swing set in 1 1/2 hr. Working alone, it takes Kim 4 hr longer than Dal to assemble the swing set. How long would it take Dal, working alone, to assemble the swing set?
You can put this solution on YOUR website! Dal and Kim can assemble a swing set in 1 1/2 hr. Working alone, it takes Kim 4 hr longer than Dal to assemble the swing set. How long would it take Dal, working alone, to assemble the swing set?
.
Let d = time it takes for Dal alone
then
d+4 = time it takes for Kim
.
1.5(1/d + 1/(d+4)) = 1
multiplying both sides by d(d+4):
1.5(d+4 + d) = d(d+4)
1.5(2d+4) = d^2+4d
3d+6 = d^2+4d
6 = d^2+d
0 = d^2+d-6
0 = (d+3)(d-2)
d = {-3, 2}
toss out the negative solution leaving:
d = 2 hours (Dal's time working alone)
