Chapterwise Quant Quiz For SSC CGL 2016: Average
Dear Readers,
As
SSC CGL exam is coming near, many of candidates are studying very hard
for this exam and want to crack this exam very seriously. Many of
candidates understand this thing that QUANTITATIVE APTITUDE Section plays a pivotal role in deciding the cut-off for candidates giving this exam.
Friends, from now on We are starting an online quiz series of "Arithmetic Quant".
According to this plan, we would be publishing daily quiz of Arithmetic
maths portion from where we would cover a topic each in it and we would
update it daily.
AND ALSO THIS QUIZ SERIES IS NOT PARTICULARLY FOR SSC EXAM BUT ALSO USEFUL FOR OTHER GOVERNMENT EXAM.
1.The
average of marks obtained by 120 candidates in a certain examination is
35. If the average marks of passed candidates is 39 and that of the
failed candidates is 15, what is the number of candidates who passed
examination?
(a) 100
(b) 200
(c) 300
(d) 400
Solution: (a)
Let the number of passed candidates be x.
Then total marks =120×25=39x+(120-x)×15
or, 4200=39x+1800-15x
or, 24x=2400
∴ x=100
∴ number of passed candidates = 100
2.A
constant distance from A to B is covered by a man at 40 km/hr. The
person rides back the same distance at 30 km/hr. Find his average speed
during the whole journey.
(a) 34 km/hr
(b) 35.29 km/hr
(c) 34.29 km/hr
(d) 35 km/hr
Solution: (c)
By the formula:
2xy/(x+y) km/hr=2*40*30/40+30
=34.29
3.A
person divides his total route of journey into three equal parts and
decides to travel the three parts with speeds of 40, 30 and 15 km/hr
respectively. Find his average speed during the whole journey.
(a) 22
(b) 24
(c) 34
(d) 44
Solution: (b)
By Formula:-
3xyz/(xy+yz+xz)
Average speed =(3×40×30×15)/(40×30+30×15+40×15)
=(3×40×30×15)/2250=24 km/hr.
4.There
were 35 students in a hostel. If the number of students increases by 7,
the expenses of the mess increase by Rs. 42 per day while the average
expenditure per head diminishes by Re 1. Find the original expenditure
of the mess.
(a) 110
(b) 220
(c) 320
(d) 420
Solution: (d)
Suppose the average expenditure was Rs. x. Then total expenditure =35x.
When 7 more students join the mess, total expenditure =35x+42
Now, the average expenditure =(35x+42)/42=x-1
or, 35x+42=42x-42
or, 7x=84∴ x=12
Thus the original expenditure of the mess=35×12= Rs. 420
5.There
were 40 students in a hostel. If the number of students increases by 8,
the expenses of the mess increase by Rs. 48 per day while the average
expenditure per head diminishes by Rs. 2. Find the original expenditure
of the mess.
(a) Rs. 620
(b) Rs. 720
(c) Rs. 750
(d) Rs. 820
Solution: (b)
Suppose the average expenditure was Rs. x. Then total expenditure =40x.
When 7 more students join the mess, total expenditure =40x+48
Now, the average expenditure =(40x+48)/48=x-2
or, 40x+48=48x-96
or, 8x=144∴ x=18
Thus the original expenditure of the mess=40×18= Rs. 720
6.The
average weight of a group of 15 boys was calculated to be 60 kg and it
was later discovered that one weight was misread as 24 kg instead of the
correct one of 42 kg. The correct average weight is?
(a) 60.2 kg
(b) 61.2 kg
(c) 62 kg
(d) 61 kg
Solution: (b)
=15*60-24+42/15= (900+18)/15
=61.2
7.The
average of Suresh’s marks in English and History is 55. His average of
marks in English and Science is 65. What is the difference between the
marks which he obtained in History and Science?
(a) 40
(b) 60
(c) 20
(d) Data inadequate
Solution : (c)
E+H= 55*2=110
E+S= 65*2= 130
= 130-110 = 20
8.The
population of a town increased by 20% during the first year, by 25%
during the next year and by 44% during the third year. Find the average
rate of increase during 3 years.
(a) 36.87%
(b) 37.68%
(c) 38.67%
(d) None of these
Solution: (c)
Let the initial population be 100
Population after the first year =100×1.20=120
Population after the second year =120×1.25=150
Population after the third year =150×1.44=216
Net increase =216-100=116
Net per cent increase during 3 years =116/100×100=116%
Net per cent increase per year =116/100×100=116%
Net increase= 116%/3 = 38.67%
9.The
average age of a husband and wife was 23 years when they were married 5
years ago. The average age of the husband, the wife and a child who was
born during the interval, is 20 years now. How old is the child now?
(a) 9 months
(b) 1 year
(c) 3 years
(d) 4 years
Solution: (d)
Present total age of husband and wife =(2×23+2×5)=56 years
Present total age of husband, wife and child =3×20=60 years.
Present age of child =(60-56)=4 years.
10.The
average height of 40 students is 163 cm. On a particular day, three
students A, B, C were absent and the average of the remaining 37
students was found to be 162 cm. If A, B have equal heights and the
height of C be 2 cm less than that of A, find the height of A.
(a) 176 cm
(b) 166 cm
(c) 180 cm
(d) 186 cm
Solution: (a)
Let the height of A, B and C be x cm, x cm and (x-2) cm
Then, x+x+(x-2)=(163×40-162×37).
∴x=176 cm
