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A man is boat intends to cross river fro...

A man is boat intends to cross river from A. If he rows perpendicular to the banks then he takes `t_1` = 10 minutes to reach the other bank and he reaches point C at a distance l = 120 m down the stream from the point B which is exactly opposite to A on the other bank. If he heads at a certain angle `alpha` to the straight path AB against the current he will reach point B in `t_2` = 12.5 minutes.

The width of river is-

A

180 m

B

200m

C

220 m

D

none of these

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The correct Answer is:
B
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