Question

To find the present age of Rishi, which statements can be dispensed.
I. In ten years,Richard will be twice as old as Rishi was 10 years ago.
II. Richard is now 9 years older than Rishi.
III. Five years ago, Rishi was 9 years younger than Richard.

• A. Only II
• B. Only III
• C. Either I or II
• D. None of the three statements can be dispensed with

Answer 1

Answer: (C)

Either I or II

There are 2 unkown variables, Rishi's age x and Richard's age y.

Each of the following statements give relation between x and y.

Statement I says: $y+10=2x.$

Statement II says: $y=x+9$

Statement III says: $y-5=(x-5)+9$= Statement II.

To solve for 2 unknown we require 2 equations.

Since, Statement II and Statement III are equivalent , either can be dispensed with.