Question
‘P’, ‘Q’ and ‘R’ can finish a task in 12
days, 36 days and 72 days respectively. ‘P’ and ‘Q’ begin the task. After ‘n’ days, ‘P’ leaves and ‘R’ joins ‘Q’. If the total work is completed in 20 days, find the value of 2n.Solution
ATQ,
Let the total work be 72 units (LCM of 12, 36, 72) Efficiency of ‘P’ = 72 / 12 = 6 units/day Efficiency of ‘Q’ = 72 / 36 = 2 units/day Efficiency of ‘R’ = 72 / 72 = 1 unit/day ATQ, (6 + 2) × n + (2 + 1) × (20 - n) = 72 Or, 8n + 3(20 - n) = 72 Or, 8n + 60 - 3n = 72 Or, 5n = 12 Or, n = 2.4 Required value = 2 × 2.4 = 4.8
Complete the series choosing the missing number.
8, 13, 20, ____, 40.
0.5 1.5 5 ? 76 385
...Given below are two numbers series 'I' and 'II' and each series has a wrong (odd one out) number. The number that should come in place of the wrong num...
21     84      168      172     ?     348
...9 15 90 95 475 479
6 a b c d e
Find the value of c.
...35    57    101    189    ?     717
100Â Â Â 180Â Â Â 294Â Â Â 448Â Â Â 648Â Â Â ?
18 113 559 2247 6721 13451
...20Â Â Â 60Â Â Â Â 150Â Â Â Â 300Â Â Â 450Â Â Â ?
Select the number from among the given options that can replace the question mark (?) in the following series.
2, 6, 12, 20, ?, ?
