There are 6 persons arranged in a row. Another person has to shake hands with 3 of them so that he should not shake hands with two consecutive persons. In how many distinct possible combinations can the handshakes take place?
UPSC-2021
A bag contains 20 balls. 8 balls are green, 7 are white and 5 are red. What is the minimum number of balls that must be picked up from the bag blindfolded (Without replacing any of it) to be assured of picking at least one ball of each colour?
UPSC-2017
The number of parallelograms that can be formed from a set of four parallel lines) intersecting another set of four parallel lines, is
UPSC-2019
Suppose you have sufficient amount of rupee currency in three denominations: 1, 10 and 50. In how many different ways can you pay a bill of 107?
UPSC-2019
How many five-digit prime numbers can be obtained by using all the digits 1, 2, 3, 4 and 5 without repetition of digits?
UPSC-2020
How many different sums can be formed with the denominations ₹ 50,₹ 100,₹ 200,₹ 500 and₹ 2,000 taking at least three denominations at a time?
UPSC-2020
