15h + 80 = 140
If you wanted to solve how many hours he worked:
15h + 80 = 140
15h = 60
h = 4.
Step-by-step explanation:
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Answer:
umm the answer to 7-11 is 69
Step-by-step explanation:
7. Always
8. sometimes
9. never
10. never
11. always
New pump:
5 hours = 1 pool
1 hour = 1/5 pool
Old pump:
15h = 1 pool
1h = 1/15 pool
If both work together
1h = 1/5 + 1/15 = 4/15 pool
4/15 pool = 1 hour
1/15 pool = 1/4 hour
15/15 pool = 1/4 x 15
1 pool = 3.75 hours or 3 hours 45 mins