Question
A man can row 10 km/h in still water. When the river is
running at a speed of 4.5 km/h, then it takes him 2 h to row to a place and comes back to the initial point . How far is the place (in km) (rounded off to two decimal places)?Solution
Upstream speed = (10 - 4.5) km/h ⇒ 5.5 km/h Downstream speed = (10 + 4.5) km/h ⇒ 14.5 km/h Let the distance of the place be x km. According to the question, (x/5.5) + (x/14.5) = 2 ⇒ (20x × 10 × 10)/(55 × 145) = 2 ⇒ x = (2 × 55 × 145)/(20 × 10 × 10) ⇒ x = 7.975 ∴ The distance of the place will be 7.98 km.
The sum of three consecutive odd natural numbers each divisible by 3 is 81. Which number is the largest number among the three numbers?
What is the ratio of the sum of the squares of the first 8 natural numbers to the sum of the first 12 odd natural numbers?
- A room contains three shelves: the 1st, 2nd, and 3rd. The number of books on the 1st and 2nd shelves are in the ratio of 6:11, while the number of books on...
- Instead of multiplying a number by 0.9, a student accidentally used 9. His result turned out to be 3510 more than the actual result. What is the original n...
Two numbers P and Q are in the respective ratio 7: 9 and their sum is 80. Then, P is equal to:
The sum of the digits of a two-digit number is 9. If 27 is subtracted from the number, its digits switch their places. What is the number?
The value of √(56+√(56 +√(56+ √(56+√56+ ................ )) )) is
Aman is forming pairs of two natural numbers, A and B, such that their product equals 350. He wants to determine how many such pairs exist where A and B...
Find the maximum value of (x + y) if 7x52y4 is divisible by 12.
