Question
The two places are 60 km apart. A and B start walking
towards each other at the same time and meet each other after 6 hours. Had A traveled with 2/3rd of his speed and B traveled with a double of his speed, they would have met after 5 hours. The speed of A is:Solution
Let the speeds of ‘A’ and ‘B’ be ‘x’ km/h and ‘y’ km/h, respectively According to the question, (x + y) = (60/6) = 10 km/h Multiplying throughout by (2), we get (2x + 2y) = 20………. (I) Also, (2x/3) + 2y = 12 Or 2x + 6y = 36……. (II) Subtracting equation (I) from equation (II), we get ‘y’ = 4 km /h putting the value of y in the equation (ii) x = 6km /h
Select the number from among the given options that can replace the question mark (?) in the following series.
8, 27, 64, 125, 216, ?
52 25 27 ? 208 1648
...15, 65, 165, 315, ?, 765
366Â Â Â 276Â Â Â 196Â Â Â 126Â Â Â 66Â Â Â ?
23 48 98 198 ? 798
...21 23 26 ? 39 51
...3 5 ? 75 1125 84375
...Compute Σ (1 / (k(k+1))) from k = 1 to 10.
56, 57, 49, 76, 12, ?
98    148    185    ?     228    238
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