Question
The speed of the boat A and B in still water are in the
ratio 15:13. The speed of the current for both boats is 16 km/hr. If the sum of time taken by boat A in downstream to travel 184 km and time taken by boat B to travel 40 km in upstream is 8 hours. Find the sum of the speed of boat A in upstream and B in downstream.Solution
Let the speed of the boats ‘A and ‘B’ in still water be ‘15x’ km/hr and ‘13x’ km/hr, repectively Speed of boat ‘A’ in downstream = (15x+16) km/hr Speed of boat ‘B’ in upstream = (13x-16) km/hr According to the question, {184/((15x+16) )}+{40/((13x-16) )} = 8 [23/(15x+16)] + [5/(13x-16)] = 1 23(13x-16) + 5(15x+16) = (15x+16)(13x-16) 299x - 368 + 75x + 80 = 195x2 - 240x + 208x - 256 374x - 288 = 195x2 - 32x - 256 195x2 - 406x - 32 = 0 on solving we get value, x=2 Speed of the boat A and B in still water is 30km/hr and 26 km/hr . Speed of boat A in upstream = 30-16 = 14 km/hr Speed of the boat B in downstream = 26+16 = 42 km/hr Required sum = 14km/hr +42 km/hr = 56 km/hr.
The arithmetic means of the following data is.23,17,20,19,21,20,20
A ball is thrown from a height of 900 m on the ground. It bounces (2/3)Â times of its every last bounce. Find the total distance covered by the ball ti...
A spent 36% and 25% of his monthly salary on food and rent, respectively. Of the remaining amount, he gave 25% and 40% to his mother and brother, respec...
The mode and the mean of grouped data are 25 and 29.5 respectively. Find the median, correct to two places of decimal, using empirical relation.
Calculate the mean of these values:
25, 30, 28, 27, 29, 26, 32, 31
The 4th term of an AP is 17 and the 9th term is 42. Find the sum of the first 20 terms.
If the number 9458k2 is divisible by 8, then find the number of possible values of 'k'.
The interest earned when a sum is invested at simple interest of 25% p.a., for 3 years, is Rs. 1875. What will be the total amount received after 2 year...
If p:q = 5:7 and p + q = 408, then find the value of (q - p).
What is the median of the following list of numbers: 5, 3, 6, 9, 11, 19,12,20, and 1?