Question 418676
One pipe fills 1/8 of the tank per minute.
The other fills 1/12 of the tank per minute.
Together, they fill 1/8 + 1/12 per minute = 3/24 + 2/24 = 5/24
5/24 tank per minute --> 24/5 minutes per tank
= 4.8 minutes
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Use the shortcut, product/sum
8*12/(8+12) = 96/20
= 4.8 minutes