Question
Ratio of still water speeds of three boats is 3:4:5. The
first boat travels downstream, the second and third boats travel upstream. They travel in streams of speed ratio 2:2:3 so that the ratio of effective speed of the boats is 5:2:2. If the effective speed of the first boat is 15 km/hr more than the effective speed of the third boat, what is the sum of their still water speeds?Solution
Ratio of their still water speeds = 3:4:5 Let their still water speeds be 3x, 4x and 5x Stream speed is in the ratio 2:2:3 Let the stream speeds be 2y, 2y and 3y ∴ Their effective speeds are (3x + 2y), (4x - 2y), (5x - 3y) respectively. (3x + 2y): (4x - 2y): (5x - 3y) = 5:2:2 => (3x + 2y)/5 = (4x - 2y)/2 => 20x - 10y = 6x + 4y => 14x = 14y => x = y ∴ Their effective speeds are 5x, 2x and 2x respectively. Given, 5x = 2x + 15 => 3x = 15 => x = 5 Sum of their still water speeds = 3x + 4x + 5x = 12x = 12 ×  5 = 60 km/hr.
Last people to adopt new practices and are traditional:
Training and Visit system; a extension approach also called
As per NABARD norms what distance should be maintained by dairy and poultry farm away from rural godowns?
What is the name of the improved variety of the national flower Lotus launched by CSIR-National Botanical Research Institute?
What nutrient deficiency leads to the development of the "Red leaf disorder" in cotton plants?
What is the end product of the nitrification process in the nitrogen cycle?
The inhibition of lettuce seed germination at temperatures higher than 30°C is an example of:
What constitutional amendment led to the incorporation of Panchayat Raj institutions in India?
Angoumois belongs to which orderÂ
Who was the recipient of the World Food Prize in 2023?
Relevant for Exams:
