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# Maths Questions for DSSSB Exam (Solutions)

Q1. Two trains A and B crosses the same platform in 12 and 18 seconds respectively. The respective length of trains A and B is 160 metres and 200 metres and the respective ratio of their speeds is 4:3. What is the length of platform?
(a) 110 m
(b) 160 m
(c) 150 m
(d) 125 m
Q2.A car dealer gives a discount of 22.5% on marked price of cars. Ashok purchases a car in Rs. 2,32,500. What is the marked price of car?
(a) Rs. 3,00,500
(b) Rs. 3,04,000
(c) Rs 3,00,000
(d) Rs 3,06,000
Q3.The difference between present ages of Rakhi and Suman is 22 years. After 6 years, Rakhi’s age is thrice of Suman’s age. What will be Rakhi’s age after 3 years?
(a) 28 years
(b) 27 years
(c) 35 years
(d) 30 years
Q4.Two persons X and Y enter into a business by investing their sum in the ratio of 5 : 8. After 5 months, Y leaves the business. After nine month, if share of Y in total profit is Rs.2,760, what is the total profit (in rupees)?
(a) 5,658
(b) 5,865
(c) 5,685
(d) 5,586
Q5.In a 72 litre mixture of glucose and water, the ratio of glucose to water is 3 : 5. What amount of glucose should be added to this mixture to make the ratio of glucose to water 4 : 5 ?
(a) 9 li
(b) 10 li
(c) 8 li
(d) 6 li
Q6.If the average of 5 consecutive odd numbers is 35. Find the product of smallest and highest number.
(a) 1209
(b) 1211
(c) 1213
(d) 1217
Q7.IF the CP of 18 article is same as that of SP of 20 article. Find the loss percentage.
(a) 10%
(b) 20%
(c) 15%
(d) 18%
Q8.The CI on a certain amount for 2 year and 3 years are Rs.210 and Rs.331 respectively. Find the rate of interest.
(a) 10%
(b) 11%
(c) 12%
(d) 13%
Q9.Find the probability of selecting 2 blue ball from a bag containing blue ball and 10 black ball.
(a) 28/153
(b) 27/151
(c) 29/153
(d) 28/163
Q10. The difference in the probability of selecting 1 blue Ball and 2 Blue balls is 8/49. If total balls are 50, find the number of blue balls.
(a) 10
(b) 15
(c) 20
(d) 8
Solutions:
S1. Ans.(b)
Sol.
Let length of plat form = x m
∴((x+160)/12)/((x+200)/18)=4/3
⇒ 9x + 1440 = 8x + 1600
⇒ x = 160 m
S2. Ans.(c)
Sol.
Marked price =2,32,500×100/77.5
= Rs. 3,00,000
S3. Ans.(d)
Sol.
Let present age of Rakhi = x years
And present age of Suman =(x-22) years
ATQ,
x + 6 = 3 (x – 22 + 6)
⇒ 2x = 54
⇒ x = 27 years
⇒ Required answer = 30 years
S4. Ans.(b)
Sol.
(X’s profit) : (Y’s profit) = 5 × 9 : 8 × 5
= 9 : 8
∴ Total profit =17/8×2760
= Rs. 5,865
S5. Ans.(a)
Sol.
Initial quantity of glucose =72×3/8
= 27 li
Initial quantity of water =72×5/8
= 45 li
Let x li glucose is added
∴(27+x)/45=4/5
⇒ 5x = 180 – 135
⇒ 5x = 45
⇒ x = 9 li
S6. Ans.(a)
Sol.
Avg. of 5 odd no. is = 35
Let a = 35
∴ smallest no. among them = a – 4
= 35 – 4
= 31
Highest among them = a + 4
= 35 + 4
= 39
∴ Reqd. answer = 31 × 39 = 1209
S7. Ans.(a)
Sol.
Since no. of article for SP is more than article of CP
∴ there will be loss.
∴ Loss percentage=[(20 –18)/20]×100
=10%
S8. Ans.(a)
Sol.
CI for 2 yr = 210
CI for 3 yr = 331
D = difference = 331 – 210 = 121
R = Rate of Interest
∴D/(CI for 2 year)=(100+R)^2/((200+R)100)
=121/210=(100+R)^2/(200+R)100
∴ R = 10%
S9. Ans.(a)
Sol.
Blue ball = 8
Black ball = 10
∴ Required probability
=8/18×7/17
=28/153
S10. Ans.(a)
Sol.
Total balls = 50
Blue balls = x
Probability of selection of 1 blue ball = x/50
Probability of selection of 2 blue balls =(x×(x –1))/(50×49)
Now x/50-x(x –1)/(50×49)=8/49
∴ x = 10 or 40