Question
Working alone, B can complete the work in 30 days. C is
twice as efficient as B and A takes 3 days more than it takes C to complete the work. Working together, in how much time would they be able to complete 7 such works?Solution
Time taken by B to complete the work = 30 days Time taken by C to complete the work = 30/2 = 15 days Time taken by A to complete the work alone = 15 + 3 = 18 days Work done by A, B and C together in 1 day. ⇒ (1/30 + 1/15 + 1/18) = (3 + 6 + 5)/90 = 14/90 this means if would take 45/7 days for A, B and C to complete the work together ∴ Time taken A, B and C to complete 7 works = 7 × 45/7 days = 45 days
230 192 172 ? 122 100
...What value should come in the place of (?) in the following number series?
64, 80, 104, ?, 176, 224
97, 106, ?, 195, 411, 460
What will come in place of the question mark (?) in the following series?
29, 42, ?, 95, 135, 184
Find the missing term:
2, 6, 15, 31, 56, ?
32   48   96   ?   720   2520
82, 98, 130, 178, 242, ?
4 10 ? 62.5 156.25 390.625
...140, 146, 170, 224, ?, 470
7 47 ? 223 359 527
...
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