Question
Arjun covers a distance of 96 km downstream and then
returns the same distance upstream, completing the entire journey in 7 hours. Given that the speed of the stream is 4 km/h, what is the speed of the boat in still water?Solution
ATQ;
Let boat speed in still water = b km/h
Downstream speed = b + 4
Upstream speed = b – 4
Total time = (96 ÷ (b + 4)) + (96 ÷ (b – 4)) = 7
Checking the factors of 96, (28+4 and 28−4 are both factors)
Check: downstream = 28 + 4 = 32 km/h, upstream = 28 – 4 = 24 km/h
Time = 96/32 + 96/24 = 3 + 4 = 7 hours
24.99% of 1619.78 + (1259.84 ÷ 12.24) = ? × 16.98
13.232 + 19.98% of 549.99 = ? × 8.99
25.31% of 5199.90 + (19.9 × 17.11) + 46.021 =? + 168.98
What approximate value will come in place of the question mark (?) in the following question? (Note: You are not expected to calculate the exact value.)...
? * 4.89 = (410.15 ÷ 13.97) % of 6190 - 1342.77
(74.93% of 640.11 + 3/4 of 359.79)² - (1/3 of 80.87 × 2)² = ?
? = {29.7% of (97.72 × 40.04)} ÷ 3.92
√81.02 + 11.836 of 24.98 = ?2 + 20.01
