M4maths Previous Puzzles

27 May 2010 2mm drop of water?

A tank contains 1 litre of water. Water is falling drop wise from the tank. Radius of the drop is 2 mm.
If every drop takes 1 sec. to fall from the tank, then the total time required to make the tank empty is

OPtion

1) 8h 16m 25s
2) 8h 17m 37s
3) 8h 15m 23s
4) 8h 10m 21s
5) 8h 3m 24s
6) 8h 13m 35s
7) 8h 11m 28s
8) 8h 22m 56s
9) 8h 19m 34s
10) 8h 23m 23s

Solution

Total amount of water = 1 litre = 1000000 cubic mm
Volume of 1 drop of water = 4*π*r*r*r/3 = 4*π*2*2*2/3 cubic mm and this drop takes 1 sec to fall from the tank
Hence total time taken = 1000000/(32*π/3) sec.
= 29856.688 sec.
= 29856.688/3600 hours
= 8.2935244 h
= 8h 17m 37s

Correct Option: 2 Best Solution (4)

sanjib biswas   15 years AGO

1000000/(4/3*3.14*8)= option 2

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SUDESHNA SEN   15 years AGO

1 litre= 1000000 cubic mm
Radius of the drop is 2 mm. and every drop takes 1 sec. to fall from the tank, then the total time required to make the tank empty is
1000000/(4/3* 3.14* 8)sec= 29857 sec= 8h 17m 37s.....Opyion 2)

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Mamon Sengupta   15 years AGO

1 litre= 1000000 cubic mm
Radius of the drop is 2 mm.and every drop takes 1 sec. to fall from the tank, then the to tal time required to make the tank empty is
= 1000000/(4/3*3.14*8)sec= 29857 sec= 8h 17m 37s....Option 2)

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Trishita Dasgupta   15 years AGO

1 litre= 1000000 cubic mm
Radius of the drop is 2 mm.and every drop takes 1 sec. to fall from the tank, then the to tal time required to make the tank empty is
= 1000000/(4/3*3.14*8)sec= 29857 sec= 8h 17m 37s....Option 2)

Like? Yes (1) | No