We all love to have chilled drinks in summers. So here's a nice problem related to orange juice.
A jug contains 15 glasses of Orange Juice. When you open the tap at the bottom it takes 12 seconds to fill a glass with juice. If you leave the tap open, how long will it take to fill the remaining 14 glasses and thus empty the jug. This time can be expressed as , then find .
Details and Assumptions :
Consider the jug to be a cylinder.
all 15 glasses are indistinguishable.
and are square free positive integers.
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Assume that,
Initially, the jug contains 1 5 W amount of liquid.
Because the jug is cylindrical, then the volume of liquid inside is given by,
V = A h
h = A V (1)
By Toricelli's Law, the velocity of the liquid pouring out of the opening is given by,
v = 2 g h
Thus,
d t d V = − B 2 g h using eq (1)
d t d V = − B A 2 g V
V − 1 / 2 d V = − B A 2 g d t (2)
Since it takes 1 2 s e c o n d s to fill one glass of juice, we could integrate eq (2),
∫ 1 5 W 1 4 W V − 1 / 2 d V = ∫ 0 1 2 − B A 2 g d t
2 ( 1 4 W − 1 5 W ) = − 1 2 B A 2 g
6 1 5 − 1 4 = B A W 2 g (3)
Let T be the time it takes to fill the remaining glasses, we would integrate eq (2) again,
∫ 1 4 W 0 V − 1 / 2 d V = ∫ 0 T − B A 2 g d t
− 2 1 4 W = − B T A 2 g
2 1 4 = T ( B A W 2 g ) using eq (3)
2 1 4 = T ( 6 1 5 − 1 4 )
1 5 − 1 4 1 2 1 4 = T
Thus,
( a , b , c , d ) = ( 1 2 , 1 4 , 1 5 , 1 4 )
a + b + c + d = 1 2 + 1 4 + 1 5 + 1 4 = 5 5