# Mathematics Questions for NDA, CDS & CAPF: Quiz-2

**Q1. The radius of the sphere 3x**

^{2}+3y^{2}+3z^{2}-8x+4y+8z-15=0 is(a) 2

(b) 3

(c) 4

(d) 5

**Q5. The distributions X and Y with total number of observations 36 and 64 and means 4 and 3, respectively are combined. What is the mean of the resulting distribution X + Y?**

(b) 3.32

(c) 3.36

(d) 3.42

**Q7. The radius of the circle passing through the point P (6, 2), two of whose**

**diameter are x + = 6 and x + 2y = 4 is**

(b) 2√5

(c) 6

(d) 4

**Q8. The coefficient of x**

^{(-n)}in (1+x)^{n}(1+1/x)^{n}is(a) 0

(b) 1

(c) 2

^{n}

(d) 2n

**Q11. If A = {4n+2|n is a natural number} and B = {3n|n is a natural number}, then what is (A ∩ B) equal to?**

(a) {12n

(b) {24n-12|,n is a natural number}

(c) {60n+30|,n is a natural number}

(d) {12n-6|,n is a natural number}

^{2}+6n|, n is a natural number}(b) {24n-12|,n is a natural number}

(c) {60n+30|,n is a natural number}

(d) {12n-6|,n is a natural number}

**Q13. The shadow of a tower standing on a level plane is found to be 50 m longer when the Sun’s elevation is 30° than when it is 60°. The height of the tower is**

(a) 25 m

(b) 25 √3 m

(c) 50 m

(d) 50 √3 m

**SOLUTIONS**

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