Question
Two pipes A and B can fill a tank in 12 min., and 16
min, respectively. If both the pipes are opened simultaneously, after how much time A should be closed so that the tank is full in 12 minutes?Solution
Let A be closed after x minutes. Then, Part filled by (A + B) in x min. + part filled by B in (12 – x) min. = 1 x (1/12 + 1/16 ) + (12 – x ) × 1/16 = 1 ⟹ (7 x)/48 + (12 - x)/16 = 1 ⟹ (7 x)/48 + 3/4 - x/16 = 1 ⟹ (4 x)/48 = 1/4 ∴ x = 3 ∴ Hence, A must be closed after 3 minutes.
Given below are three series I, II and III. Each series consist an odd one out number. Odd one out number in series I, II and III are 'P', 'Q' and 'R',...
7Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 6 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 45 Â Â Â Â Â Â Â Â Â 40 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 312 Â Â Â Â Â ...
96Â Â Â 111Â Â Â 131Â Â Â ? Â Â Â Â Â 186Â Â Â Â 221
Study the given pattern carefully and select the number that can replace the question mark (?) in it.
4 7 6
15 ? 21
44 68 60
205     255     292     ?     335     345
...2120 1976 2097 1997 ? 2014
...If  2,  7, 20,  x ,  110,  235,
Then,  7 x + 7√x = ?
20    60      180      540     ?     4860
...5184, ?, 432, 144, 36, 12
3, 7, 16, 35, ?, 153
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