Question

A student has to opt for 2 subjects out of 5 subjects for a course, namely, Commerce, Economics, Statistics, Mathematics I and Mathematics II. Mathematics II can be offered only if Mathematics I is also opted. The number of different combinations of two subjects which can be opted is  

(a) 5 (b) 6 (c) 7 (d) 8

Answer 1

(c) It mathematics I is not opted, then two subjects

out of four subjects have to be opted for.

∴  Number of ways in which two subjects can be

If mathematics II is opted, then it can be offered only if mathematics I is also opted for Number of ways in which two subjects can be opted for = 6 +1 = 7.