Question
Two inlet pipes 'A' and 'B' can fill an empty tank in 15
minutes and 20 minutes, respectively. Another outlet pipe 'C' can empty the tank in 60 minutes. If all the three pipes are opened together, then find the time taken by them to fill the tank.Solution
Let the total capacity of the tank be 60 litres (LCM of 15, 20, and 60).
Efficiency of 'A' = 60 ÷ 15 = 4 litres/minute
Efficiency of 'B' = 60 ÷ 20 = 3 litres/minute
Efficiency of 'C' = 60 ÷ 60 = -1 litre/minute
Required time = 60 ÷ (4 + 3 - 1) = 60 ÷ 6 = 10 minutes
Find the wrong number in the given number series.
120, 126, 138, 162, 220, 306
217Â Â Â Â 210Â Â Â Â Â 236Â Â Â Â Â 299Â Â Â Â Â 423Â Â Â Â 640
...112, 222, 440, 872, 1717 , 3424
In each of the following giving number series, a wrong number is given. Find out the wrong number?
82, 81, 86, 110, 168, 287
- 78, 86, 71, 95, 60, 112
2100, 2140, 2186, 2240, 2300, 2372
9, 10, 12, 18, 42, 160
A-5,  A,  35,  52, 78, 115
Find the wrong number in the given number series.
233, 206, 183, 152, 125, 98
Find the wrong number in the given number series.
2, 4, 12, 48, 120, 1440
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