Question
Quantity I. Two pipes A and B can fill a tank in 12
minutes and 16 minutes respectively. If both the pipes are opened simultaneously, after how much time should B be closed so that the tank is full in 9 minutes? Quantity II. Two pipes A and B can fill a tank in 24 minutes and 48 minutes respectively. If both the pipes are opened simultaneously, after how much time should B be closed so that the tank is full in 18 minutes? Study the following information carefully and answer the Questions given below:Solution
Quantity I. Let B be closed after x minutes. Then, part filled by (A + B) in x min. + part filled by A in (9 – x) min = 1 x (  1/12  +  1/16  ) +  (9 – x ) ×  1/12  = 1 Or  7x/48  +  (9-x)/12  = 1or  7 x + 36 – 4 x  = 48 ∴ 3 x = 12 or  x  = 4 Quantity II. Let B be closed after x minutes. Then, part filled by (A + B) in x min. + part filled by A in (18 – x) min = 1 x (  1/24  +  1/48  ) +  (18 – x ) ×  1/24  = 1 Or  3x/48  +  (18 -x)/24  = 1or  3 x + 36 – 2 x  = 48 ∴  x = 12 Hence Quantity I < Quantity IIÂ
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...What will come in place of the question mark (?) in the following series?
12, 13, 27, ?, 329, 1646
7   4   5   9   20    ?    160.5
60, 120, ?, 160, 32, 192
80, 120, 30, 45, 9, 13.5, ?
45, ?, 84, 114, 151, 195
12, 12, 30, 120, ?, 4620
Find the missing number, in the given number series.
6, 12, 36, ?, 720, 4320
64, 80, 120, 210, ?, 945
8, 12, 20, 32, 52, ?, 136
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