Home Tests Defence NDA / CDS Mathematics

Defence NDA / CDS
Mathematics

NDA & CDS MCQ questions — Mathematics, English, GK, Reasoning for defence exams.

30 Q 4 Subjects 12th / Graduate
Take Mock Test
Difficulty: All Easy Medium Hard 1–10 of 30
Advertisement
Q.1 Medium Mathematics
In GP: 2,6,18,54... 5th term?
A 108
B 162
C 216
D 180
Correct Answer:  B. 162
EXPLANATION

This question asks you to find the 5th term of a geometric progression using the formula for the nth term.

Step 1: Identify the first term and common ratio.

First term: a = 2

Common ratio: r = 6/2 = 3 (or 18/6 = 3, or 54/18 = 3)

Step 2: Write the formula for the nth term of a GP.

The nth term of a GP is given by:

\[a_n = a \cdot r^{n-1}\]
Step 3: Substitute values for the 5th term (n = 5).
\[a_5 = 2 \cdot 3^{5-1}\]
\[a_5 = 2 \cdot 3^4\]
Step 4: Calculate the result.
\[a_5 = 2 \cdot 81 = 162\]

Therefore, the 5th term = 162

The answer is (B) 162

Take Test
Q.2 Medium Mathematics
Determinant of [[1,2],[3,4]]?
A -2
B 2
C -4
D 4
Correct Answer:  A. -2
EXPLANATION

For a 2×2 matrix, the determinant is calculated using the cross-product formula: (top-left × bottom-right) minus (top-right × bottom-left).

Step 1: Identify the matrix elements.

Matrix = [[1, 2], [3, 4]]

where a = 1, b = 2, c = 3, d = 4

Step 2: Apply the determinant formula for 2×2 matrix.
\[\text{Det} = ad - bc\]
Step 3: Substitute the values.
\[\text{Det} = (1)(4) - (2)(3)\]
Step 4: Calculate.
\[\text{Det} = 4 - 6 = -2\]

Therefore, the determinant of [[1,2],[3,4]] = -2

The answer is (A) -2

Take Test
Q.3 Easy Mathematics
cos 60° = ?
A 1/2
B √3/2
C 1
D 0
Correct Answer:  A. 1/2
EXPLANATION

This question tests your knowledge of standard trigonometric values for common angles.

Step 1: Recall the standard angle values

The trigonometric ratios for 0°, 30°, 45°, 60°, and 90° are fixed values that must be memorized for competitive exams.

Step 2: Identify cos 60° from the standard table

For 60°, the cosine value is:

\[\cos 60° = \frac{1}{2}\]
Step 3: Verify using the unit circle concept

At 60°, if you place a point on the unit circle, the x-coordinate (which represents cosine) equals \(\frac{1}{2}\).

Step 4: Eliminate other options

- \(\sin 60° = \frac{\sqrt{3}}{2}\) (option B is sine, not cosine)

- \(\cos 0° = 1\) (option C)

- \(\cos 90° = 0\) (option D)

Therefore, \(\cos 60° = \frac{1}{2}\)

The correct answer is A) 1/2

Take Test
Q.4 Medium Mathematics
10th term of AP: 2,5,8,11...?
A 29
B 32
C 28
D 30
Correct Answer:  A. 29
EXPLANATION

To find the nth term of an arithmetic progression, we use the formula \(a_n = a + (n-1)d\) where a is the first term and d is the common difference.

Step 1: Identify the first term and common difference.

From the AP: 2, 5, 8, 11...

First term a = 2

Common difference d = 5 - 2 = 3

Step 2: Write the formula for the 10th term.

We need to find \(a_{10}\) using:

\[a_n = a + (n-1)d\]
Step 3: Substitute n = 10, a = 2, and d = 3.
\[a_{10} = 2 + (10-1) \times 3\]
\[a_{10} = 2 + 9 \times 3\]
\[a_{10} = 2 + 27\]
\[a_{10} = 29\]

Therefore, the 10th term of the AP is 29.

The answer is (A) 29.

Take Test
Q.5 Medium Mathematics
Integrate ∫2x dx?
A x²+C
B 2x²+C
C x+C
D 2x+C
Correct Answer:  A. x²+C
EXPLANATION

Integration is the reverse process of differentiation, and we use the power rule to find antiderivatives.

Step 1: Identify the integral form

We need to find ∫2x dx, which means we're integrating the function 2x with respect to x.

Step 2: Apply the power rule of integration

The power rule states: ∫x^n dx = \(\frac{x^{n+1}}{n+1}\) + C

Rewrite 2x as: ∫2x^1 dx

Step 3: Factor out the constant

∫2x dx = 2∫x^1 dx

Step 4: Apply the power rule
\[2∫x^1 dx = 2 \times \frac{x^{1+1}}{1+1} + C = 2 \times \frac{x^2}{2} + C = x^2 + C\]
Step 5: Verify by differentiation

\(\frac{d}{dx}\)(x² + C) = 2x ✓

Therefore, ∫2x dx = x² + C

Answer: (A) x²+C

Take Test
Advertisement
Q.6 Easy Mathematics
HCF of 24 and 36?
A 6
B 8
C 12
D 18
Correct Answer:  C. 12
EXPLANATION

HCF (Highest Common Factor) is the largest number that divides both given numbers without leaving a remainder.

Step 1: Find all factors of 24

Factors of 24 = 1, 2, 3, 4, 6, 8, 12, 24

Step 2: Find all factors of 36

Factors of 36 = 1, 2, 3, 4, 6, 9, 12, 18, 36

Step 3: Identify common factors

Common factors = 1, 2, 3, 4, 6, 12

Step 4: Select the highest common factor

The largest common factor = 12

Alternative Method - Using Prime Factorization:

24 = 2³ × 3

36 = 2² × 3²

HCF = 2² × 3 = 4 × 3 = 12

Therefore, HCF of 24 and 36 = 12

The answer is (C) 12

Take Test
Q.7 Medium Mathematics
45° in radians?
A π/4
B π/3
C π/2
D π/6
Correct Answer:  A. π/4
EXPLANATION

To convert degrees to radians, use the conversion formula that relates the two angle measurement systems.

Step 1: Recall the conversion formula from degrees to radians.
\[\text{Radians} = \text{Degrees} \times \frac{\pi}{180°}\]
Step 2: Substitute 45° into the formula.
\[\text{Radians} = 45° \times \frac{\pi}{180°}\]
Step 3: Simplify the fraction.
\[= \frac{45\pi}{180} = \frac{\pi}{4}\]

Therefore, 45° = \(\frac{\pi}{4}\) radians.

The answer is (A) π/4

Take Test
Q.8 Easy Mathematics
Slope of y = 3x + 5?
A 5
B 3
C -3
D -5
Correct Answer:  B. 3
EXPLANATION

The slope of a line is the coefficient of x in the standard linear equation form y = mx + c.

Step 1: Identify the standard form of a linear equation.

The equation of a line is written as: y = mx + c, where m is the slope and c is the y-intercept.

Step 2: Compare the given equation with standard form.

Given equation: y = 3x + 5

Standard form: y = mx + c

Step 3: Extract the slope.

Here, m = 3 (coefficient of x) and c = 5 (constant term)

Therefore, the slope is 3.

The answer is (B) 3

Take Test
Q.9 Medium Mathematics
7! (7 factorial) = ?
A 2520
B 5040
C 720
D 1260
Correct Answer:  B. 5040
EXPLANATION

Factorial is the product of all positive integers from 1 up to a given number.

Step 1: Understand factorial notation

7! means 7 × 6 × 5 × 4 × 3 × 2 × 1

Step 2: Multiply step by step
\[7! = 7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1\]
Step 3: Calculate from left to right

7 × 6 = 42

42 × 5 = 210

210 × 4 = 840

840 × 3 = 2520

2520 × 2 = 5040

5040 × 1 = 5040

Therefore, 7! = 5040

The answer is (B) 5040

Take Test
Q.10 Medium Mathematics
Solve: x² - 5x + 6 = 0
A x=2,3
B x=1,6
C x=3,4
D x=2,4
Correct Answer:  A. x=2,3
EXPLANATION

This question asks you to find the roots of a quadratic equation using factorization.

Step 1: Write the equation in standard form.
\[x^2 - 5x + 6 = 0\]
Step 2: Find two numbers that multiply to give 6 (constant term) and add to give -5 (coefficient of x).

The numbers are -2 and -3, because:

(-2) × (-3) = 6

(-2) + (-3) = -5

Step 3: Factorize the quadratic.
\[(x - 2)(x - 3) = 0\]
Step 4: Solve for x by setting each factor equal to zero.

x - 2 = 0 → x = 2

x - 3 = 0 → x = 3

Step 5: Verify by substituting back.

For x = 2: (2)² - 5(2) + 6 = 4 - 10 + 6 = 0 ✓

For x = 3: (3)² - 5(3) + 6 = 9 - 15 + 6 = 0 ✓

Therefore, x = 2, 3

The answer is (A).

Take Test
IGET
iget AI
Online · Ask anything about exams
Hi! 👋 I'm your iget AI assistant.

Ask me anything about exam prep, MCQ solutions, study tips, or strategies! 🎯
UPSC strategy SSC CGL syllabus Improve aptitude NEET Biology tips