# CASE STUDY QUESTION 20-Class X-Maths

CASE STUDY QUESTION 20-Class X-Maths

On a bright Sunday morning three friends A, B and C decided to go on river for fishing and boating. They decided to leave for the place together in the evening. The journey was smooth, it just went as scheduled then they reached to the river, and started to set the boat on sail. They were enjoying their ride with full speed. They started boating from a place to another place which is at a distance of 42 km and then again returns to the starting place. They took 20 hours in all. The time taken by them riding downstream in going 14 km is equal to the time taken by them riding upstream in going 6 km.

For calculating they took speed of the boat as x km/hr and the speed of the river as y km/hr. Based on the above situation, answer the following questions:

(i) The speed of the boat in downstream is
(a) x + y km/hr (b) x – y km/hr (c) x y km/hr (d) x/y km/hr

Sol: x + y km/hr

(ii) The speed of the boat in upstream is
(a) x + y km/hr (b) x – y km/hr (c) x y km/hr (d) x/y km/hr

Sol: x – y km/hr

(iii) The speed of the boat in still water is
(a) 5 km/hr (b) 2 km/hr (c) 7 km/hr (d) none of these

Sol: 5 km/hr

(iv) The speed of the river is
(a) 5 km/hr (b) 2 km/hr (c) 7 km/hr (d) none of these

Sol: 2 km/hr

(v) The speed of boat in upstream is
(a) 5 km/hr (b) 2 km/hr (c) 3 km/hr (d) 6 km/hr

Sol: Speed of the boat in upstream = 5 – 2 = 3 km/hr

Detailed Solution of Question no. (iii) & (iv)

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