2
8
þ
3 : 6
8
þ
3 : 6
12
¼ 1
0 : 25 þ 0 : 45 þ 0 : 3 ¼ 1
1 ¼ 1
EXAMPLE:A swimming pool can be filled in 6 hours and drained in 15
hours. How long will it take to fill the pool if the owner has forgotten to close
the drain valve?
SOLUTION:
GOAL: You are being asked how long in hours it will take to fill the pool if
the drain is left open.
STRATEGY: Letx¼the time in hours it takes to fill the pool.
Rate Time ¼Amount of work done
Fill pool^1
6
x^1
6
x
Empty pool^1
15
x^1
15
x
Since the drain is emptying the pool, the equation is
1
6
x
1
15
x¼ 1
IMPLEMENTATION: Solve the equation:
1
6
x
1
15
x¼ 1
The LCD is 30.
305
1
x
61
302
1
x
151
¼ 30 1
5 x 2 x¼ 30
3 x¼ 30
186 LESSON 17 Solving Work Problems