Sunita cuts a sheet of paper into three pieces. Length of first piece is equal to the average of the three single digit odd prime numbers. Length of the second piece is equal to that of the first plus one-third the length of the third. The third piece is as long as the other two pieces together. The length of the original sheet of paper is
Answer & explanation
Answer: (d) 30 units
The single-digit odd primes are 3, 5 and 7, so the first piece is 5 units. With the third piece T, the second is 5 + T/3 and T = 10 + T/3, so T = 15, the second piece is 10 and the sheet is 30 units.
- Single-digit odd primes: 3, 5, 7; average = 15/3 = 5, so the first piece = 5.
- Let the third piece be T; the second = 5 + T/3.
- Third = first + second: T = 5 + 5 + T/3 → 2T/3 = 10 → T = 15.
- Second = 5 + 15/3 = 10.
- Sheet = 5 + 10 + 15 = 30 units.
- Check: the third piece (15) equals 5 + 10.
Remember · If one part equals the sum of the others, the whole is twice that part.
Question and answer: UPSC's official GS Paper II (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·