SSC CGL 2025 Tier-I · 23 September 2025, Shift 3 · Quantitative Aptitude · Question 13 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.

The average of 5 different numbers is 24. If the smallest number is 15, what is the average of the remaining four numbers?

(a)27.25
(b)26.25
(c)25.5
(d)24.5

Answer

Why

Correct — B. Turn the average into a total, take out the known number, then average what is left.

Sum of 5 numbers = 5 × 24 = 120
Remove the smallest: 120 − 15 = 105
Average of the remaining four = 105 ÷ 4 = 26.25 → option (b)

Check: 15 is 9 below 24, so the remaining four sit 9 above it in total, 9 ÷ 4 = 2.25 each: 24 + 2.25 = 26.25.

Why the others are wrong

(a)
27.25 — 27.25 × 4 = 109, and 109 + 15 = 124. That would make the average of all five 24.8, not 24.
(c)
25.5 — 25.5 × 4 = 102, and 102 + 15 = 117, an average of 23.4 for all five instead of 24.
(d)
24.5 — 24.5 barely moves off 24. Taking out a number 9 below the average lifts the rest by 9 ÷ 4 = 2.25, not 0.5.

Concept

Average × count = total. Work in totals, then divide at the end.

Removing a value below the average pushes the average of what remains up. Here 15 sits 9 below 24, and the remaining four make up that 9 between them, 2.25 each.

The words 'different' and 'smallest' do not change the arithmetic. They tell you the remaining four are all larger than 15.

Key facts

Total = average × number of items.
New average after removing one value = (old total − value) ÷ (count − 1).
If the removed value is k below the average of n items, the rest average k ÷ (n − 1) more.

Study next

Average after adding or replacing one member of a groupAverage of the rest after a sub-group leavesFinding a wrongly recorded value from a corrected average

Common traps

Dividing 105 by 5 instead of 4: 21 is below the original average, which cannot happen when a below-average value leaves.
Adding the whole gap to the average (24 + 9 = 33): the 9 is shared by four numbers.

The same remove-and-divide step, with a group instead of one number, is 13 Sep 2025, 16:00, Quant Q.8: 24 employees average ₹40,000 and 8 seniors ₹60,000, so the remaining 16 average (9,60,000 − 4,80,000) ÷ 16 = ₹30,000.

Related PYQs

No directly related past PYQ was found.

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