Let's denote Bishnu's current age by B and Anil's current age by A. We are given: The product of their ages is 240 : A×B=240. Twice Bishnu's age is 4 years more than Anil's age: 2B=A+4 Step 1: Express Anil's age in terms of Bishnu's age. From the second equation, A=2B−4 Step 2: Substitute this expression into the product equation. Replacing A in A×B=240 gives: (2B−4)×B=240. Step 3: Simplify and solve for B. Multiply out the left side: 2B2−4B=240 Divide the entire equation by 2 : B2−2B=120 Rearrange it into standard quadratic form: B2−2B−120=0 Step 4: Factor the quadratic equation. We need two numbers that multiply to -120 and add to -2 . These numbers are -12 and 10 . Hence, we factor: (B−12)(B+10)=0
Step 5: Solve for B. Set each factor equal to zero: ‌B−12=0⇒B=12 ‌B+10=0⇒B=−10 Since age cannot be negative, we discard B=−10 and accept B=12. Step 6: Find Bishnu's age 2 years ago. Bishnu's age 2 years ago is: 12−2=10 Thus, Bishnu's age 2 years ago was 10 years. The correct answer is Option A: 10 year.