Question
Pipe ‘A’ can fill a tank in 15 hours whereas leak
‘A’ can empty it in 45 hours. If they both operate along with pipe ‘B’, then the given tank gets filled in 9 hours. How much time is needed to fill the given tank if pipe ‘B’ and leak ‘A’ work together? ÂSolution
Let the capacity of the tank be 45 litres {LCM (15 and 45)} Efficiency of pipe ‘A’ = 45 ÷ 15 = 3 litres/hour Efficiency of leak ‘A’ = 45 ÷ 45 = 1 litres/hour Combined efficiency of pipe ‘A’ and leak ‘A’ = 3 – 1 = 2 litre/hour Combined efficiency of pipe ‘A’, ‘B’ and leak ‘A’ = 45 ÷ 9 = 5 units/hour Efficiency of pipe ‘B’ = 5 – 2 = 3 units/hour Time taken by pipe ‘B’ and leak ‘A’ to fill the tank = 45 ÷ (3 – 1) = 22.5 hours
107    157    194    ?     237    247
...(248 + 352)/(34 - 30) = ?
290, 571, 900, ?, 1485, 1890
32   48   96   ?   720   2520
64, 65, 73, 100, ?, 289
8    12    39      ?       180    216
...What value should come in the place of (?) in the following number series?
5670, 1620, 540, 216, 108, ?
Find the missing number, in the given number series.
60, 150, ?, 450, 450, 225
What will come in place of the question mark (?) in the following series?
325, 292, 262, 229, ?, 166
Find the missing number in the given number series.
 1165, ?, 1040, 985, 935, 890Â
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