Question
Sandeep can solve 20 questions in 1 hour. If he
decreased his efficiency by 20%, then how much time would he take to solve the same number of questions?Solution
1 hour = 60 minutes Initial efficiency of Sandeep = 60 ÷ 20 = 3 minutes/question New efficiency of Sandeep = 60 ÷ (20 x 0.8) = 3.75 minutes/question So, time required to finish 20 questions = 3.75 x 20 = 75 minutes Alternate Solution Ratio of new efficiency to old efficiency = 0.8:1 = 4:5 Therefore, ratio of time taken now to ratio of time taken initially = 5:4 Required time taken = 60 x (5/4) = 75 minutes
107    157    194    ?     237    247
...9 28 83 250 ? 2248
55, 71, 119, 199, 311, ?
5, 5, 15, 75, ?, 4725
7 29 61 ? 211 349
...23, 39, 64, 100, ?, 213
What will come in place of the question mark (?) in the following series?
45, 66, 44, 67, 43, ?
246, 102, 202, ?, 174, 158
216, 81, 297, 378, ?, 1035, 1728
Find the missing number in the given number series.
1, 2, 6, 24, 120, ?
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