A question paper consists of five problems, each problem having three internal choices. In how many ways can a candidate attempt one or more problems?

A. 63
B. 511
C. 1023
D. 15
Explanation:
Given that, the question paper consists of five problems. For each problem, one or two or three or none of the choices can be attempted.
Hence, the required number of ways = 45 – 1.
= 210 – 1 = 1024 – 1 = 1023