Three pipes P, Q and R can fill a tank in 6 hours. After working at it together for 2 hours, R is closed and both P and Q can fill the remaining part in 7 hours. The number of hours that will be taken by R alone to fill the tank is

A train running at 18 km per hour crosses a mark on the platform in 9 seconds and takes 25 seconds to cross the platform. If P is the length of the train and Q is the length of the platform in meters, then (P, Q) = ___________.

What is the area of an equilateral triangle whose inscribed circle has radius R?

What is the probability of getting a sum of 22 or more when four dice are thrown?

The number of all integers n for which n² + 96 is a perfect square, is

Given below are two statements: A number of distinct 8-letter words are possible using the letters of the word SYLLABUS. If a word is chosen at random, then Statement I: The probability that the word contains the two S's together is 1/4. Statement II: The probability that the wor…

Given below are two statements: Statement I: The number of ways to pack six copies of the same book into four identical boxes, where a box can contain as many as six books, is 9. Statement II: The minimum number of students needed in a class to guarantee that there are at least s…

Let a, b and c be the ages of three persons P, Q and R respectively where a ≤ b ≤ c are natural numbers. If the average age of P, Q, R is 32 years and if the age of Q is exactly 6 years more than that of P, then what is the minimum possible value of c?

Given below are two statements: Statement I: The ratio of the son's age to the father's age is 1 : 5. The product of their ages is 245. The ratio of the son's age to the father's age after 9 years will be 3 : 5. Statement II: A milkman adds 30 litres of water to 70 litres of milk…