David gets on the elevator at the 11th floor of a building and rides up at the rate of 57 floors per minute. At the same time, Albert gets on an elevator at the 51st floor of the same building and rides down at the rate of 63 floors per minute. If they continue travelling at these rates, then at which floor will their paths cross ?
I have a few sweets to be distributed. If I keep 2, 3 or 4 in a pack, I am left with one sweet. If I keep 5 in a pack, I am left with none. What is the minimum number of sweets I have to pack and distribute ?
Clearly, the required number would be such that it leaves a remainder of 1 when divided by 2, 3 or 4 and no remainder when divided by 5. Such a number is 25.
53.
If a clock takes seven seconds to strike seven, how long will it take to strike ten ?
Let the father's age be x and the son's age be y.
Then, x - y = y or x = 2y,
Now, x = 36. So, 2y = 36 or y = 18.
Therefore Son's present age = 18 years.
So, son's age 5 years ago = 13 years.
56.
A fires 5 shots to B's 3 but A kills only once in 3 shots while B kills once in 2 shots. When B has missed 27 times, A has killed
In a class, 3/5 of the students are girls and rest are boys. If 2/9 of the girls and 1/4 of the boys are absent, what part of the total number of students is present ?
In a family, a couple has a son and a daughter. The age of the father is three times that of his daughter and the age of the son is half of that of his mother. The wife is 9 years younger to her husband and the brother is seven years older than his sister. What is the age of the mother ?
Let the daughter's age be x years.
Then, father's age = (3x) years.
Mother's age = (3x - 9) years; Son's age = (x + 7) years.
So, x + 7 = (3x-9)/2 ⇔ 2x + 14 = 3x - 9 ⇔ x = 23.
Therefore Mother's age = (3X - 9) = (69 - 9) years = 60 years.
59.
If a 1 mm thick paper is folded so that the area is halved at every fold, then what would be the thickness of the pile after 50 folds ?
First bunch of bananas has (1/4) again as many bananas as a second bunch. If the second bunch has 3 bananas less than the first bunch, then the number of bananas in the first bunch is