Problem: Let r and s be positive numbers with r greater than s. Let R=r+1 and S=s+1. The difference in percent by which r exceeds s and R exceeds S is:
Answer Choices:
A. r100(r−s)
B. s100(r−s)
C. r+1100(r−s)
D. s+1100(r−s)
E. none of these
Solution:
(sr−s−s+1(r+1)−(s+1))100=s(s+1)100(r−s)