Posted by Lueshelle on Wednesday, April 25, 2012 at 10:33am.
Dal and Kim can assemble a swing set in 1/1/2 hrs,working alone it takes Kim 4 hrs longer than Dal to assemble the swing set.How long would it take Dal to working alone to assemble the set
intermediate algebra - Steve, Wednesday, April 25, 2012 at 11:40am
Dal takes d
Kim takes k
Dal&Kim take b (for both)
1/b = 1/d + 1/k
1/(3/2) = 1/d + 1/(d+4)
2/3 = 1/d + 1/(d+4)
multiply through by 3d(d+4) to get
2d(d+4) = 3(d+4) + 3d
2d^2 + 8d = 3d + 12 + 3d
2d^2 + 2d - 12 = 0
d^2 + d - 6 = 0
(d+3)(d-2) = 0
d = -3 or 2
must have positive time, so d=2
That is, Dal takes 2 hours by himself
1/2 + 1/6 = 2/3 = 1/(3/2)
Answer This Question
More Related Questions
- algebra - Dal and kim can assemble a swing set in 1.5 hours. working alone it ...
- Intermediate Algebra - Dale and Kim can assemble a swing set in 1 1/2 hours....
- Math word problem 2 - Sabine and Hercule can assemble a table in 45 minutes. ...
- Math - Bryan and Kim are painting a house. Working together they can paint a ...
- HSE - Two companies working together can clear a parcel of land in 8 hrs. ...
- math - It takes B 6 hours longer than A to assemble a machine. together they can...
- Algebra - It takes matt 9 hrs longer to build a wall than it takes chris. ...
- math - Filling a tank. Two pipes are connected to the same tank. Working ...
- Alegebra - Working alone it takes Jerry 9 hrs to mop a warehouse. Ruth can mop ...
- Algebra - Two pipes are connected to the same tank. When working together...