Teaching CSIR NET Mock Test Series Mathematics Permutations and Combinations Fundamental Principles of Counting
A boy can escape through a window of size at least 4 feet. The 28 windows of a house are of sizes 2, 3, 4 or 5 feet and their numbers are proportional to their sizes. The number of windows available for the boy to escape through is
1
2
2
9
3
10
4
18