SSC CGL 2025 Tier-I · 23 September 2025, Shift 1 · Quantitative Aptitude · Question 14 of 100

We transcribed this text from the pictures on a candidate's response sheet for this shift; the answer is the key SSC colour-marked on that sheet. Solution last reviewed 13 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. From 2025 the candidate response sheet prints every question and option as a picture, so the text here is transcribed from those pictures for this shift and checked against them independently; where the layout carries meaning, the picture is shown as well. Each answer is the key SSC colour-marked on that sheet. SSC released a tentative key for challenge and later its final one, both only to candidates behind a login, and the sheet does not say which of the two it carries. The solutions are written by UnlockIAS.

A group of 5 friends went to a restaurant. If 4 of them paid Rs. 200 each and the fifth paid Rs. x, the average bill per person came out to be Rs. 210. What is the value of x?

(a)Rs. 250
(b)Rs. 270
(c)Rs. 260
(d)Rs. 280

Answer

Why

Correct — A. Work with the total bill.

Total = average × people = 210 × 5 = Rs. 1,050
Paid by the four = 4 × 200 = Rs. 800
Fifth friend: x = 1,050 − 800 = Rs. 250 → option (a).

Check: 800 + 250 = 1,050, and 1,050 ÷ 5 = 210.

Why the others are wrong

(b)
Rs. 270 — Rs. 270 makes the total 800 + 270 = 1,070, and 1,070 ÷ 5 = Rs. 214, not the stated Rs. 210.
(c)
Rs. 260 — Rs. 260 gives a total of 1,060 and an average of Rs. 212. The fifth friend has to cover just the Rs. 40 the four paid below 210.
(d)
Rs. 280 — Rs. 280 gives a total of 1,080 and an average of Rs. 216. It sits 70 above the average, but the four fall short by only 4 × 10 = Rs. 40.

Concept

An average hides a total: total = average × count. Once the total is known, a missing value is the total minus the known values.

The deviation route skips the big numbers. Each of the four paid 10 below the Rs. 210 average, a shortfall of 40. The fifth must pay 40 above it: 210 + 40 = 250.

Key facts

Total = average × number of items: 210 × 5 = 1,050.
Missing value = total − sum of the known values: 1,050 − 800 = 250.
Deviations from an average sum to zero: 4 × (−10) + 40 = 0.

Study next

Change in average when one person joins or leaves a groupA middle value from overlapping averages (first six and last six of eleven numbers)Combined average of two groups of different sizes

Common traps

Spreading the Rs. 40 shortfall across all five people instead of loading it onto the fifth friend.
Multiplying the average by 4 friends instead of 5 when forming the total.

The same total-minus-known step settles 22 Sep 2025, 09:00, Quant Q.14: a supervisor joining 40 workers lifts the average from Rs. 24,000 to Rs. 24,500, so the supervisor earns 41 × 24,500 − 40 × 24,000 = Rs. 44,500.

Related PYQs

No directly related past PYQ was found.

Topic: Averages — all 76 SSC CGL questions on it, every solved shift.