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# Important Questions of Maths For DSSSB Exams

Q1. The angle between the external bisectors of two angles of a triangle is 60°. Then the third angle of the triangle is
(a) 40°
(b) 50°
(c) 60°
(d) 80°

Q2. In a regular polygon, the exterior and interior angles are in the ratio 1 : 4. The number of sides of the polygon is:
(a) 10
(b) 12
(c) 15
(d) 16

Q3. An exterior angle of a regular polygon is 72°, then sum of all the interior angles is:
(a) 360°
(b) 480°
(c) 520°
(d) 540°

Q4. Two parallel chord of length 30 cm and 16 cm are on opposite side of centre of circle of radius 17 cm then find distance of one chord from another chord.
(a) 20
(b) 21
(c) 22
(d) 23

Q7. At certain rate of simple interest Rs. 1600 amounted to Rs. 1840 in 5 years. If the rate of interest be decreased by 3%, what will be the amount after 5 years?
(a) 1200
(b) 1680
(c) 1600
(d) 1500
Q8. In an examination, average marks obtained by the girls of a class is 85 and the average marks obtained by the boys of the same class is 87. If the girls and boys are in the ratio 4 : 5, average marks of the whole class (approx.) is closest to
(a) 86.1
(b) 85.9
(c) 86.5
(d) 86.4

Q9. In trapezium ABCD, AB ∥ CD and AB = 2CD. Its diagonals intersect at O. If the area of ∆ AOB = 84 cm^2, then the area of ∆ COD is equal
(a) 42 cm^2
(b) 26 cm^2
(c) 72 cm^2
(d) 21 cm^2

Q10. The simple interest on a sum of money is 8/25 of the sum. If the number of years is numerically half the rate percent per annum, then the rate percent per annum is
(a) 5
(b) 8
(c) 6 (1/4)
(d) 4
Solutions

S2. Ans.(a)
Sol. (n – 2)/2=4/1
n – 2 = 8
n = 10

S3. Ans.(d)
Sol. Number of sides = (360°)/72 = 5
Sum of interior angle = (n – 2) × 180°
= (5 – 2) × 180°
= 540°

S4. Ans.(d)
Sol. Trick = (30 + 16)/2=46/2 = 23

S7. Ans.(c)
Sol. 1840 – 1600 = 240
240/5=48
(48/1600)×100=3%
3% – 3% = 0
P.A. =amount = 1600

S8. Ans.(a)
Sol. G = 85 × 4
= 340
B = 87 × 5
= 435
Total = 340 + 435 = 775
Average =775/9
= 86.1

S10. Ans.(b)
Sol.
(8P/25)=(P×r×r)/200
r = 8