Question
Ratio of speed of boat in downstream and speed of stream
is 9:4, if speed of current is 8 km/hr, then find distance travelled (in km) upstream in 5 hours. Section 4Solution
Given: Ratio of (speed of boat in downstream) : (speed of stream) = 9 : 4 Speed of stream = 8 km/h Let common multiplier = k So, Speed of stream = 4k = 8 => k = 8 / 4 = 2 Speed of boat in downstream = 9k = 9 × 2 = 18 km/h Let speed of boat in still water = b km/h Speed of stream = 8 km/h Downstream speed = b + 8 = 18 => b = 18 - 8 = 10 km/h Upstream speed = b - speed of stream = 10 - 8 = 2 km/h Distance travelled upstream in 5 hours: = speed × time = 2 × 5 = 10 km
4, 5, 11, 34, 137, ?
216, 81, 297, 378, ?, 1035, 1728
What will come in place of (?) question mark in the given number series.
960, 960, 480, ?, 40, 8
What will come in place of the question mark (?) in the following series?
12, 13, 27, ?, 329, 1646
864, 432, 144, ? , 7.2, 1.2
What will come in place of the question mark (?) in the following number series?
29, 30, 33, ?, 69, 150
What will come in place of the question mark (?) in the following series?
47, 56, 120, 145, ?, 410
30          162        344        ?             890        1270
...70, 69, 73, 64,80, 55, ?
120, 136, 111, 147, ?, 162
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