Question
A boy goes to school with a speed of 80 km/h and comes
back with a speed of 45 km/h. find his average speed?Solution
Since the distance travelled by a boy (going to school and coming back from school) is equal. So, average speed = 2xy/(x + y) Average speed = (2 x 80 x 45)/(80 + 45) Average speed = (2 x 80 x 45)/125 = 57.6 km/hr
There are three series given below which are following with the same pattern.
Series I: 21, 44, 135, 544, 2725
Series II: 14, B, C, D, E
90     211     67     236     ?     265
...26 63 124 215 342 511 ?
...23   27    54    ?       195    231
...59, 170, 301, 452, ?, 814
30, 39, 66, ? , 174, 255
2, 12, 36, 80, ?, 252
104   106   110   113   ?   126
17                          26                          37                   �...
13, 14, 18, 27, 43, ?
