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Two places are X km apart. Two boats start from each place at the same time towards each other. One is going upstream and another downstream. The speeds of two boats are 12 km/hr and 15 km/hr. Both the boats meet after 4 hours. From the given statement which of the following can be determined? A. Speed of the current. B. Value of X. C. If both the boats travel upstream (Faster boat is behind the slower one) then after how much time will they meet? D. If both the boats travel downstream (Faster boat is behind the slower one) then after how much time will they meet?

Two places are X km apart. Two boats start from each place at the same time towards each other. One is going upstream and another downstream. The speeds of two boats are 12 km/hr and 15 km/hr. Both the boats meet after 4 hours. From the given statement which of the following can be determined? A. Speed of the current. B. Value of X. C. If both the boats travel upstream (Faster boat is behind the slower one) then after how much time will they meet? D. If both the boats travel downstream (Faster boat is behind the slower one) then after how much time will they meet? Correct Answer Only B, C and D

Suppose the speed of the current = ‘s’ km/hr;

The speeds of two boats are 12 km/hr and 15 km/hr;

When the boats travel towards each other, they meet after 4 hours:

⇒ X = (12 + x + 15 – x) × 4

⇒ X = 108 km

When the boats travel in the same direction (Faster boat is behind the slower one):

Suppose both the boats are moving upstream:

∴ Time after which the boats will meet = 108/ = 108/3 = 36 hours

Suppose both the boats are moving downstream:

∴ Time after which the boats will meet = 108/ = 108/3 = 36 hours

Speed of the current can’t be determined.

∴ Only B, C and D can be determined.

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