If x and y are two digits and the number 4x5y790 is divisible by 11, then what is the remainder, if x + y is divided by 11?
Quantitative Aptitude ·Previously asked in UPSC Civil Services Examination 2026
View the full solved paper: GS Paper II
Question
If x and y are two digits and the number 4x5y790 is divisible by 11, then what is the remainder, if x + y is divided by 11?
- A. 1
- B. 3
- C. 5
- D. 7 (Correct answer)
Correct Answer
Option D — 7
Detailed Solution & Explanation
The correct answer is Option D (7).
Key Points
- For 4x5y790 to be divisible by 11, the alternating digit sum must be a multiple of 11: (4 + 5 + 7 + 0) − (x + y + 9) = 7 − (x + y).
- This is divisible by 11 when x + y = 7 (or 18); in both cases the remainder of (x + y) ÷ 11 is 7.
Additional Information
- The alternating-sum rule for 11 pins x + y ≡ 7 (mod 11), giving remainder 7 → Option D.