A man rows his boat 75 km downstream and 45 km upstream, taking 5 hours each time. Find the speed of the stream?
Options:
(A) 6 kmph
(B) 5 kmph
(C) 2 kmph
(D) 3 kmph
(E) 1 kmph
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Speed downstream = d/t = 75/(5) = 15 kmph
Speed upstream = d/t = 45/(5) = 9 kmph
The speed of the stream = (15 - 9)/2 = 3 kmph So the answer is: (D).
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Find the area of the quadrilateral of one of its diagonals is 20 cm and its off sets 9 cm and 6 cm?
Options:
(A) 128
(B) 150
(C) 887
(D) 279
(E) 771
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1/2 * 20(9 + 6) = 150 cm2 So the answer is: (B).
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Four of the five parts numbered (a),(b),(c),(d) and (e) in the following equation are exactly equal. Which of the parts is not equal to the other four? The number of that part is the answer.
Options:
(A) (a – b) 2 + 4ab
(B) a(a + b)  + b(a + b) 
(C) (a2 – b2)  + 2b(b + a) 
(D) (a – b) b + (a + b) 2b
(E) (a + b) 2 – 2a(a – b)  + a(2a – 2b) 
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The other parts are equal to (a + b)2. So the answer is: (D).
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