SSC CGL 2025 Tier-I · 16 September 2025, Shift 2 · Quantitative Aptitude · Question 19 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 tent designed as a triangular prism features a triangular base with an area of 20 m² and a height of 6 m. What is the volume of this tent?

(a)100 m³
(b)120 m³
(c)130 m³
(d)140 m³

Answer

Why

Correct — B. Any prism has volume = base area × height, where the height is the distance between its two identical end faces.

Base area (given) = 20 m²
Height of the prism = 6 m
Volume = 20 × 6 = 120 m³ → option (b)

The ½ of the triangle's area formula is already inside the 20 m², so nothing is halved again.

Why the others are wrong

(a)
100 m³ — 100 m³ ÷ 20 m² = 5 m, a height the tent does not have. With the stem's 6 m, base area × height = 20 × 6 = 120 m³.
(c)
130 m³ — 130 m³ ÷ 20 m² = 6.5 m, half a metre more than the 6 m in the stem. The volume is 20 × 6 = 120 m³.
(d)
140 m³ — 140 m³ ÷ 20 m² = 7 m, a metre more than the 6 m given. Base area × height stops at 120 m³.

Concept

A prism has two identical, parallel end faces joined by flat sides. Slice it parallel to the ends and every slice is the same shape as the base.

That is why its volume is simply base area × height. Only the base-area formula changes from prism to prism.

For a triangular base the area is ½ × base × altitude of the triangle. This question has already done that step and given 20 m².

The sentence could be read as giving the triangle's own height as 6 m. That reading leaves the tent's length unknown, so no volume could be found.

The workable reading, and the one the key's 120 m³ uses, takes 6 m as the prism's height: the distance between its two triangular ends.

Key facts

Volume of a right prism = area of base × height.
Lateral surface area of a right prism = perimeter of base × height.
A pyramid on the same base and height holds one-third of the prism's volume.

Study next

Lateral and total surface area of a triangular prismFinding the side of a prism's square base from its volume and heightVolume of a pyramid, one-third of the prism on the same base and height

Common traps

Halving again: the 20 m² already includes the triangle's ½, so ½ × 20 × 6 = 60 m³ counts it twice.
Using the pyramid rule ⅓ × 20 × 6 = 40 m³ for a prism, whose two ends are identical.

Also asked 12 Sep 2025, 16:00, Quant Q.21 (a triangular prism's volume after its height rises by 20%) and 21 Sep 2025, 16:00, Quant Q.14 (the side of a square base from volume and height). Each is base area × height, read forwards or backwards.

Related PYQs

No directly related past PYQ was found.

Topic: Right Prism, Right Circular Cone, Right Circular Cylinder, Sphere, Hemispheres, Rectangular Parallelepiped, Regular Right Pyramid with triangular or square base — all 99 SSC CGL questions on it, every solved shift.