A boat moves upstream at the rate of 1 km in 20 minutes and down stream 1 km in 12 minutes. Then the speed of the current is :
Options:
(A) 1 kmph
(B) 2 kmph
(C) 3 kmph
(D) 2.5 kmph
(E) 3.5 kmph

Rate upstream = (1/20 *60) = 3 kmph
Rate dowm stream = 1/12 * 60 = 5 kmph
Rate of the current = (5-3) = 1 kmph So the answer is: (A).

In a certain animal population, for each of the first 3 months of life, the probability that an animal will die during that month is 1/10. For a group of 700 newborn members of the population, approximately how many would be expected to survive the first 3 months of life?
Options:
(A) 511
(B) 546
(C) 552
(D) 562
(E) 570

Number of newborns that can die in first month = 1/10 * 700 = 70
Survived = 630
Number of newborns that can die in second month = 1/10 * 630 = 63
Survived = 567
Number of newborns that can die in third month = 1/10 * 567 = 56
Survived = 511 So the answer is: (A).

What is the least number should be added to 1056, so the sum of the number is completely divisible by 26?
Options:
(A) 10
(B) 20
(C) 30
(D) 40
(E) 50

(1056 / 26) gives remainder 16
10 + 16 = 26, So we need to add 10 So the answer is: (A).

If 10 crates have 95 apples each and how many apples more is required in order to make 100 apples in each crate?
Options:
(A) 5
(B) 10
(C) 15
(D) 50
(E) 0
Each crate requires 5 apples and totally there are 10 crates so required apples = 10 * 5 = 50 So the answer is: (D).