Question
Length of train 'X' is (35n - 30) metres, which is 200
metres more than that of train 'Y'. Time taken by 'X' and 'Y' to cross a pole is 20 seconds and 16 seconds, respectively. Sum of speeds of both the trains is (3n + 1) m/s. Determine the time taken by 'Y' to cross a platform of length 275 metres.Solution
ATQ, Length of 'Y' = 35n - 30 - 200 = (35n - 230) metres Speed of 'X' = [(35n - 30) ÷ 20] m/s Speed of 'Y' = [(35n - 230) ÷ 16] m/s 
4 X (35n - 30) + 5 X (35n - 230) = (3n + 1) X 80 Or, 140n - 120 + 175n - 1150 = 240n + 80 Or, 75n = 1,350 Or, 'n' = 18 Length of 'Y' = 600 - 200 = 400 metres Speed of 'Y' = (400/16) = 25 m/s Required time = (400 + 275) ÷ 25 = 27 seconds
10Â Â Â Â Â Â Â Â 6Â Â Â Â Â Â Â Â Â Â Â Â Â Â 5Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 8.5Â Â Â Â Â Â Â Â Â Â 16Â Â Â Â Â Â Â Â Â Â Â Â Â ?
...17Â Â Â Â Â ? Â Â Â Â Â 2142 Â Â Â Â Â Â 12852 Â Â Â Â Â Â 64260Â Â Â Â Â Â 257040
...19, 37, 65, 91, 127, 169
31                          16.5                       18                     �...
73920, 9240, ?, 220, 44, 11
56, 57, 49, 76, 12, ?
The following numbers form a series followed by a (?). Find the odd one out first and then find that what will come in place of the question mark (?) ac...
20 9 10 ? 29 71.5
...123   125   129   132   ?   145
13, 26, 104, ?, 13312, 425984
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