Eight identical taps, all turned on together, fill an empty tank in 45 minutes. How many such taps, all turned on together, are needed to fill the same empty tank in 30 minutes?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 12
The taps are identical, so the work needed to fill the tank is number of taps × time, and it stays the same.
Work to fill the tank \(=8\times45=360\) tap-minutes
Taps needed for 30 minutes \(\displaystyle =\frac{360}{30}=12\)
12 taps are needed.