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# Maths Questions for DSSSB Exam : 27th July 2018 (Solutions)

Q1.A shopkeeper calculated his profit on the marked price and finds it to be 30%. He forgets the fact that he gave a discount of 20%. What is his actual profit percentage?
(a) 100/7%
(b) 20%
(c) 25%
(d) 200/7%
Q2.In the year 2002, the cost price of an item was 90% of the selling price while in 2003, the cost price was 95% of the selling price. If the gross profit remains the same for both the years, what is the percentage increase in the cost price of the item from 2002 to 2003 ?
(a) 120%
(b) 95%
(c) 111%
(d) 105%
Q3.Mayank can do 50% more work than Shishu in the same time. Shishu alone can do a piece of work in 30 hours. Shishu starts working and he had already worked for 12 hours when Mayank joins him. How many hours should Shishu and Mayank work together to complete the remaining work?
(a) 6
(b) 12
(c) 4.8
(d) 7.2
Q4.There are 12 pipes connected to a tank. Some of them are fill pipes and the others are drain pipes. Each of the fill pipes can fill the tank in 8 h and each of the drain pipes can drain completely in 6 h. If all the pipes are kept open, an empty tank gets fill in 24 h. How many of the 12 pipes are fills pipes
(a) 5
(b) 6
(c) 7
(d) 8
Q5.A car goes 20 miles on a gallon of gas driving at 60 miles/h. If the car is driven at 70 miles/h it goes as far as 70%. How many gallons of gas will be required to travel 210 miles/hr.
(a) 6.17
(b) 22.5
(c) 12
(d) 15
Directions (6-10): Number of students enrolled in mechanical, electrical and civil branches of five different colleges in the year 2016
Q6.Ratio of number of male to female students in electrical discipline from college B is 16 : 9 and total professors in same college and in same branch is 100/9% of total female students from the same branch and same college then, find total number of professor in electrical branch from college B.
(a) 18
(b) 15
(c) 20
(d) 22
Q8.If 20% of students in civil branch from college E are transferred to civil branch of college C then find the ratio of students in civil from college C to the total students from college E now.
(a) 34/111
(b) 23/222
(c) 23/111
(d) 34/113
Q9.Average of students in electrical branch from all colleges are what percent less/more than the average students in Civil branch from all colleges together ? (Approximately)
(a) 12%
(b) 10%
(c) 4%
(d) 6%
Q10.If 20% of total students from College D are failed in yearly exam, 75% of total students are passed from college E in yearly exams then what will be total students in college D and E together in year 2017 if 400 more students are enrolled in 2017 from both colleges D and E together (consider both colleges were opened in 2016 and enrollment is cancelled when a student fails in exam )
(a) 2340
(b) 2900
(c) 2440
(d) 2800
Solutions:
S1. Ans.(a)
Sol.
When profit is calculated on M.P.
then C.P. = 100 – 30 (let M.P. = Rs. 100)
= 70
and S.P. = Rs. 80
∴Actual profit=(80 –70)×100/70
=14 2/7%
S2. Ans.(c)
Sol.
Let S.P. in year 2002 was Rs. x.
And in year 2003 was Rs. y
In 2002, C.P. = 0.9x
In 2003, C.P. = 0.95y
Since profit in both years is same
∴ x – 0.9x = y – 0.95y
⇒ 2x = y
∴ Required percentage
=(0.95×2 –0.9)×100 /0.9
= 111.11
≃ 111%
S3. Ans.(d)
Sol.
Mayank can do the whole work alone in
30×2/3=20 hours
Let in x hours they complete the remaining work together
∴(12+x)/30+x/20=1
⇒ 24 + 2x + 3x = 60
⇒ x = 7.2 hours
S4. Ans.(c)
Sol.
Let x are fill pipes out of 12 pipes
∴ x fill pipes can fill the tank in 8/x hours
And (12 – x) drain pipes can drain the tank in 6/(12–x) hours
∴  x/8–(12–x)/6=1/24
3x – 48 + 4x = 1
⇒ 7x = 49
⇒ x = 7
S5. Ans.(d)
Sol.
In one gallon gas, car goes 20 miles at the speed 60 miles/hr.
In one gallon gas, car will go
=20×70/100=14 miles
At a speed of 70 miles/hr.
Now, if car has to cover 210 miles in one hours,
Required number of gallons of gas
=210/14=15 gallons
S6. Ans.(b)
Sol.
Total number of professors = 1/9×9/25×375=15
S7. Ans.(c)
Sol.
Number of male students in Mechanical branch from college A = 13/25×500=260
Required percentage = (300-260)×100/300
= 40/3%
=13 1/3%
S8. Ans.(a)
Sol.
20% students from civil branch in college E = 20×450/100=90
Total students of civil branch in college C = 250 + 90 = 340
Required ratio = 340/1110
= 34/111
S9. Ans.(d)
Sol.
Total students in Electrical branch in all college =350+375+375+450+325
= 1875
Total students in civil branch from all colleges = 275+300+250+500+450
= 1775
Required percentage = (375-355)×100/355
=5.6%
~ 6% more
S10. Ans.(a)
Sol.
Total students in college D and E together in 2017 who are enrolled now are
= 1300×80/100+1200×75/100+400
=2340