If a + b means a − b; a − b means a × b; a × b means a ÷ b; a ÷ b means a + b, then what is the value of 10 + 30 − 100 × 50 ÷ 25? (Operations are to be replaced simultaneously)
Answer & explanation
Answer: (d) −25
Replace every sign at once: 10 + 30 − 100 × 50 ÷ 25 becomes 10 − 30 × 100 ÷ 50 + 25. By BODMAS, 30 × 100 ÷ 50 = 60, so the value is 10 − 60 + 25 = −25.
- Swap the signs: + becomes −, − becomes ×, × becomes ÷, ÷ becomes +.
- 10 + 30 − 100 × 50 ÷ 25 becomes 10 − 30 × 100 ÷ 50 + 25.
- 30 × 100 ÷ 50 = 3000 ÷ 50 = 60.
- 10 − 60 + 25 = −25.
Remember · Rewrite the whole expression with the new signs first, then apply BODMAS; never substitute and calculate at the same time.
Question and answer: UPSC's official GS Paper II (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·