CBSE Guess > Papers > Question Papers > Class X > 2009 > Mathematics > Mathematics

Sol. Let the speed of the stream = x km/hr
Then the speed of motorboat upstream = (5 – x) km/hr
and the speed of motorboat downstream = (5 + x) km/hr
Distance = 12 km
According to the question,

24x = 25 – x²             x² + 24x – 25 = 0
(x² + 25x – 1x – 25 = 0
x (x + 25) – 1 (x + 25) = 0
(x + 25) (x – 1) = 0
x + 25 = 0 or x – 1 = 0
x = – 25 or x = 1
But speed can not be –ve
Speed of the stream = 1 km/hr.

Q. 27. A man on the deck of a ship 14 m above water level, observes that the angle of elevation ofthe top of a cliff is 60° and the angle of depression of the base of the cliff is 30°. Calculate the distance of the cliff from the ship and the height of the cliff. [Take 3 = 1.732]

Sol. Let AB be the deck of a ship and CE be the cliff.

Mathematics 2009 Question Papers Class X
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					Set 2		Set 2
					Set 3		Set 3