Question
A man can row a boat in still water at a speed of 8
km/h. He rows downstream for 1 hour and then returns upstream. If the total time taken for the entire journey is 2.5 hours, find the speed of the stream.Solution
Let the speed of the stream be x km/h. Downstream speed: Speed of boat + speed of stream = 8 + x km/h Upstream speed: Speed of boat - speed of stream = 8 - x km/h Distance downstream: Since the man rows downstream for 1 hour, the distance downstream (d) is: d = Speed × Time = (8 + x) × 1 = 8 + x km Time taken upstream: Time = Distance / Speed = (8 + x) / (8 - x) hours According to the problem, the total time for the journey is 2.5 hours: Time downstream + Time upstream = 2.5 => 1 + (8 + x) / (8 - x) = 2.5 Subtracting 1 from both sides: (8 + x) / (8 - x) = 1.5 Now, cross-multiplying: 8 + x = 1.5(8 - x) 8 + x = 12 - 1.5x x + 1.5x = 12 - 8 2.5x = 4 x = 4 / 2.5 x = 1.6 km/h Correct Answer: a) 1.6 km/h.
Statements: Â A % B & G % B; B # L & J; J @ K # S
Conclusions:
I. L @ K
II. A % K
III. S @ B
...Statements: M = R ≥ S , N = O > Q, Q > W = A < S
Conclusions :I. N ≥ S
II. W > R
III. O ≤ S
Statements: A$K; E#N; K@E
Conclusions:
I) A$N
II) A@N
Which of the following letters should be placed in the blank spaces respectively (in the same order from left to right) to complete the given expression...
What is the suitable sign that should be placed so that O > K is true, and J ≤ M is true in the relation 'J = K ≤ L ( ) M < N = O'?
Statements : Z < S < W < D; E ≤ C ≤ Y < D; U < T < S ≤ V
Conclusions :
I. V > Z
II. C < U
III. V > E
Statements: M > T, P > R, T = Q, U ≥ Q, P = U
Conclusion:
I. M ≥ R
II. R > M
Statements: T @ A % S $ L © JÂ
Conclusions:Â
 I. T % LÂ
II. T $ LÂ
III. S # J
Statements: A > C = B ≥ D ≥ F, B = G ≤ H < E
Conclusions:
I. A > G
II. H ≥ F
III. E > C
Statements: R = S > Y ≥ T = W ≥ U > V > X
Conclusions:
I. Y < X
II. S > V
III. U ≤ R
