SSC CGL 2025 Tier-I · 12 September 2025, Shift 1 · Quantitative Aptitude · Question 4 of 100

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 11 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.

From a sample of 200 software engineers, determine the ratio of those proficient in Python to those proficient in Java using the given information: Category | Number Proficient in Python and Java | 50 Proficient in Python only | 70 Proficient in Java only | 60 Proficient in neither language | 20

(a)11:12
(b)12:11
(c)7:6
(d)6:7

Answer

Why

Correct — B. Each language's total is its 'only' group plus the overlap.

Python = both + Python only = 50 + 70 = 120
Java = both + Java only = 50 + 60 = 110
Python : Java = 120 : 110
Divide both by 10: 12 : 11 → option (b)

Why the others are wrong

(a)
11:12 — 11 : 12 is Java : Python, the right numbers in the wrong order. The question asks Python to Java, so Python's 120 comes first.
(c)
7:6 — 7 : 6 is 70 : 60, the 'only' groups alone. It leaves out the 50 engineers who know both languages, and they count in each total.
(d)
6:7 — 6 : 7 is 60 : 70, Java only to Python only: the overlap is dropped and the order reversed as well.

Concept

The table lists the four non-overlapping regions of a two-circle Venn diagram: both, Python only, Java only and neither.

A set's total is its 'only' region plus the overlap, so the 50 who know both are counted once in Python's total and once in Java's.

The 20 who know neither sit outside both circles and enter neither total.

The four rows add up to the sample: 50 + 70 + 60 + 20 = 200. That check confirms the table gives separate regions, not overlapping totals.

Key facts

n(A) = n(A only) + n(A and B).
n(A or B) = n(A) + n(B) − n(A and B) = 120 + 110 − 50 = 180.
Those in neither set = total − n(A or B) = 200 − 180 = 20, matching the table.

Study next

The two-set union formula n(A ∪ B) = n(A) + n(B) − n(A ∩ B)Three-set Venn problems with 'exactly two' and 'all three' regionsReducing a ratio to lowest terms by dividing by the HCF

Common traps

Using the 'only' figures and writing 7 : 6.
Reversing the order and writing Java : Python, 11 : 12.
Adding the 20 'neither' engineers to one of the totals.

This item gives the Venn regions as a two-column table instead of a diagram and asks for the ratio of the two full sets, so the overlap has to be added back to each 'only' figure.

Related PYQs

No directly related past PYQ was found.

Topic: Ratio & Proportion — all 50 SSC CGL questions on it, every solved shift.