SSC CGL 2024 Tier-I · 13 September 2024, Shift 2 · Quantitative Aptitude · Question 17 of 99

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 10 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

The following table indicates the number of students studying in three subjects in four colleges. What is the ratio of the total number of students studying in the Physics to that of studying in Mathematics in all four colleges taken together?

(a)576 : 731
(b)776 : 603
(c)781 : 585
(d)775 : 601

Answer

Why

Correct — B. Only the Physics row and the Mathematics row are wanted — the Chemistry row is there to be passed over.

Physics: 420 + 435 + 412 + 285
= 855 + 412 + 285 = 1552

Mathematics: 256 + 310 + 295 + 345
= 566 + 295 + 345 = 1206

Ratio = 1552 : 1206, and both totals are even
= 776 : 603 → option (b)

That is fully reduced: 776 = 8 × 97 and 603 = 9 × 67 share no factor.

Why the others are wrong

(a)
576 : 731 — 576 : 731 matches neither total. Physics comes to 1552 and Mathematics to 1206, and no common divisor of those two lands on 576 or on 731.
(c)
781 : 585 — 781 : 585 is adrift in both halves, 5 above 776 and 18 below 603. Re-adding the Physics column settles it on its own: 420 + 435 + 412 + 285 = 1552, whose half is 776.
(d)
775 : 601 — 775 : 601 sits 1 below 776 and 2 below 603 — near enough to survive a quick glance, wrong in both halves. The totals are 1552 and 1206, which halve to exactly 776 and 603.

Concept

A table question rewards reading before arithmetic. The stem names two rows, Physics and Mathematics, and the phrase all four colleges taken together means each row is summed straight across W, X, Y and Z.

The Chemistry row never enters the working. It is printed between the two rows the stem wants, which is precisely why it gets picked up by mistake.

Then reduce. 1552 : 1206 both divide by 2, giving 776 : 603, and the options are printed in lowest terms, so an unreduced ratio matches nothing on screen.

The table is an image on the response sheet, so the four column headings W, X, Y and Z and all twelve cells have to be read off the picture.

Key facts

Physics across the four colleges totals 1552 students.
Mathematics across the four colleges totals 1206 students.
1552 : 1206 reduces to 776 : 603, and it stops there because 776 = 8 × 97 while 603 = 9 × 67.

Study next

Percentage-of-total questions on the same table, comparing one cell against a row sumAverage-per-college questions, which reuse the row sums and divide by fourReducing a ratio of four-digit numbers by testing 2, 3, 5 and 11 before hunting for a bigger factor

Common traps

Summing the Chemistry row because it sits between the two rows the stem names
Reading down a college column instead of across a subject row
Answering 1552 : 1206 and finding no matching option

Row-sum ratio questions on a printed table are asked at 25 Sep 2024, 09:00, Quant Q.7, comparing three printers' page counts over three days, and 9 Sep 2024, 09:00, Quant Q.16 works a table of candidates appeared against candidates present.

Related PYQs

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