Question
A boat can travel 36 km downstream in 45 min. The ratio
of the speed of the boat in still water to the speed of the stream is 5: 1. How much time will the boat take to cover 38 km upstream?Solution
Speed of downstream = D/T = 36 × (60/45) = 48 km/hr The ratio of the speed of the boat in still water to the speed of the stream = 5: 1 (5x, x) => 6x = 48 => x = 8 Speed of upstream = 5x – x = 4x = 32 km/hr Distance = 38 km Time = D/S = 38/32 = 1(1/5) hr = 1 hour 12 min
Two data sets of sizes 6 and 9 have standard deviation 3 and 4, respectively, and arithmetic means 4 and 4, respectively. The standard deviation of com...
If A and B are manually exclusive events such that P(A)P(B) > 0 , then which option is correct?
For the distribution
X: 1 0 1
P(x): 0.3 ...
A man pedals cycle from his house to his office at a speed of 10 km/h and back from the office to his house at a speed of 15 km/h. His average speed (i...
Which of the following is NOT a type of data classification?
If Z1, Z2,…Zn are n independent standard normal variates, then Σni=1 Z2i will follow:
If the first, second, and third moment about the origin are 2, 8, and 18 respectively, then third moment about mean is
The mean deviation from an average A will be minimum, if A represents:
If the occurrence of events follows Poisson Process with mean rate λ, then inter-occurrence time of events will follow:
Relevant for Exams:
