Question
A boat takes 7 hours to cover 259 km upstream and 9
hours to cover 477 km downstream. Find the time taken by the boat to cover 602 km upstream and 605 km downstream if speed of boat in still water is increased by 4 km/h and speed of stream is decreased by 2 km/h.Solution
Upstream speed = 259/7 = 37 km/h Downstream speed = 477/9 = 53 km/h Speed of boat in still water = (37 + 53)/2 = 45 km/h  Speed of stream = (53 – 37)/2 = 8 km/h Increased speed of boat in still water = 45 + 4 = 49 km/h Decreased speed of stream = 8 – 2 = 6 km/h Required time taken = 602/(49 – 6) + 605/(49 + 6) = 14 + 11 = 25 hours
Determine the sum of the first 16 odd numbers.
For which range of 'p' does the expression 19p - 2p²- 35 have a positive value??
The remainder obtained when (47³ + 35³) is divided by 41 isÂ
16Â Â Â Â Â Â Â Â Â Â 4Â Â Â Â Â Â Â Â Â Â Â Â Â 2Â Â Â Â Â Â Â Â Â Â Â Â Â 1.5Â Â Â Â Â Â Â Â Â 1Â Â Â Â Â Â Â Â Â Â Â Â Â 1.875
...The sum of the digits of a two-digit number is 9, and when the digits are reversed, the number decreases by 45. Find the changed number.
Find the unit digit of (76101 - 6).
Find the sum of all natural numbers less than 1,000 that are divisible by both 3 and 5 but not by 7.
How many times I write digit ‘1’ in first hundred natural numbers?Â
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