Averages

1.The arithmetic mean of the scores of a group of students in a test was 52. The brightest 20% of them secured a mean score of 80 and the dullest 25% a mean score of 31. The mean score of remaining 55% is:
A.51.4
B.52.6
C.56.1
D.55.3
E.None of these
Answer – A (51.4)
Explanation – Let the required mean score be a
Then, 20 x 80 + 25 x 31 + 55 x a = 52 x 100
1600 + 775 + 55a = 5200
55a = 2825
a = 51.4

2.The average of a non-zero number and its square is 5 times the number. The number is:
A.0 , 7
B.0 , 6
C.5 , 7
D.0 , 9
E.None of these
Answer – D (0 , 9)
Explanation – Let the number be x.
Then,
(x + x^2) / 2 = 5x
x^2 – 9x = 0
x (x – 9) = 0
x = 0 or x = 9.

3.If the mean of a, b, c is M and ab + bc + ca = 0, then the mean of a^2, b^2, c^2 is:
A.3 M x M
B.3 M
C.9 M
D.9 M x M
E.None of these
Answer – A (3 M x M)
Explanation –
We have :
(a + b + c) / 3 = M or (a + b + c) = 3M.
Now, (a + b + c)^2 = (3M)^2 = 9M^2
a^2 + b^2 + c^2 + 2 (ab + bc + ca) = 9M^2
a^2 + b^2 + c^2 = 9M^2
Required mean =
(a^2 + b^2 + c^2)/3= 9M^2/ 3 = 3 M^ 2

SBI PO 2015 - numerical Aptitude

1.The price of oil is increased by 20%,as a result a family decrease consumption by 25%.The expenditure of the family on oil will be
1).90%increase
2).10%incraese
3).90%decrease
4).10%increase.
4).10%increase.
Exp: (120/100)×(75/100)×100=90.
100-90=10%(should be decrease)

2.A rectangular grassy plot 110 m by 65 m has a gravel path 2.5 m wide all round it on the inside. Find the cost of gravelling the path at 80 paise per sq. Meter
1).Rs.680
2).Rs.860
3).Rs.608
4).None.
1).Rs.680
Exp: overall area of the grassy plot is 110 x  65 =7150 sq. meters.The area of the grassy plot
after applying the gravel path is  105 x 60=6300 sq. meters.Area of the gravel path is  7150 –
6300 = 850 sq.mtrs.Hence x 0.80=Rs.680 .

3.A game of the football with 11 players lasts for exactly 80minutes.There are 4 substitutes that alternate equally.If each player plays for the same length of the time,What is the duration?
1)120m
2)20m
3)84m
4)40m
2)20m
Exp: 80/4=20m.

4.20 workers working 5hours a day can finish the work in 20 days.If the workers went to work for 4hours a day.How many more workers are required to complete the work in same 20days?
1)7
2)4
3)5
4)6
3)5
Exp: workers required for 4h=>(5/4)×20=25.
25-20=5.

5.Pencils are bought at 3 for Rs.2 and sold at 2 for Rs.3.Find the gain percentage
1)100%
2)110%
3)125%
4)115%
3)125%
Exp: [3(3)-2(2)]/4=5/4
In percentage=> (5/4)×100=125%.

Mixtures And Alligations

1.Sum of Rs.118 was shared among 50 boys and girls,each girl receive Rs.2.60 and boy receive Rs.1.80.Find the number of girls.
A) 15
B)25
C)30
D)35

D)35


2.A Mixture contain 80% of sulphur,another mixture contain 70% of sulphur.In order to get 84% of sulphur,in what ratio these two must be mixed.
A) 2:7
B)7:2
C)7:4
D)4:5
B)7:2


3.In what ratio water be mixed with juice costing Rs.12 per liter to obtain a mixture worth of Rs.8 per litre?
A)2:3
B)2:1
C)1:2
D)3:2
C)1:2

4.In what proportion must sugar at Price 4.10 per kg must be mixed with weat at Price 4.60 per kg, so that the mixture be worth Rs 4.30 a Kg ?
A)3:2
B)2:3
C)5:3
D)None of these

A)3:2

5.In what proportion must water be mixed with milk to gain 40 % by selling it at cost price ?
A) 3:5
B)5:3
C)2:3
D)3:2
C)2:3   – Solution: cp=1-(40/100)=(100-40)/100
Sol: cp=1-(40/100)=(100-40)/100
=60/100=3/5.Rs
Then required ratio is 2:3

Simplification Quiz

1.(50² + 30² ) ÷ 6400 = ?
1 : 17/20
2 : 17/32
3 : 17/36
4 : 17/46
5 : None of these

2.6241 + 3284 + 1923 + 2187 + 3268 + 3147 =?
1 : 21040
2 : 20050
3 : 21150
4 : 22150
5 : None of these

3.38 × 34 + 38 × 56 + 20 × 38 = ?
1 : 2966
2 : 4180
3 : 3256
4 : 3258
5 : None of these

4.(5)³ – (3.75)³ – (1.25)³– 3(3.75) (6.25) = ?
1 : 0
2 : 1
3 : -1
4 : -2.5
5 : None of these

5.32/153 × 68/128 × 81/4 =?
1 : 9/7
2 : 9/4
3 : 8/3
4 : 7
5 : None of these

Quants Quiz : Quadratic Equations Quiz

1.I. 72×2 + x – 1 = 0
II. 63y2 – 25y + 2 = 0
1 : if x ≥ y
2 : if x > y
3 : if x < y
4 : if x ≤ y
5 : if the relation between x and y cannot be established.

2.I. 56×2 + 37x + 6 = 0
II. 66y2 – 13y – 4 = 0
1 : if x ≥ y
2 : if x > y
3 : if x < y
4 : if x ≤ y
5 : if the relation between x and y cannot be established.

3.I. 77×2 + 58x + 8 = 0
II. 42y2 + 59y + 20 = 0
1 : if x ≥ y
2 : if x > y
3 : if x < y
4 : if x ≤ y
5 : if the relation between x and y cannot be established.

4.I. 99×2 + 149x + 56 = 0
II. 156y2 + 287y + 132 = 0
1 : if x ≥ y
2 : if x > y
3 : if x < y
4 : if x ≤ y
5 : if the relation between x and y cannot be established.

5.I. 81×2 – 9x – 2 = 0
II. 56y2 – 13y – 3 = 0
1 : if x ≥ y
2 : if x > y
3 : if x < y
4 : if x ≤ y
5 : if the relation between x and y cannot be established.

SSC Reasoning Quiz

ANS-(1)

Ans- 2

ANS-4

ANS-5

Arithmetic aptitude questions

1) If 30% of a number is 12.6, find the number? 

 A.    45

B.    38

C.    40

D.    42

2) What number must be added to 6, 16 and 8 to get an average of 13? 

A.    22

B.    25

C.    20

 D.    18

3) What is the ratio of 12 minute to 1 hour ? 

 A.    2/3

 B.    3/4

C.    1/5

D.    1/4

4) 10 cats caught 10 rats in 10 seconds. How many cats are required to catch 100 rats in 100 seconds 

 A.    100

B.    10

C.    20

 D.    50

5) A man wants to reach a window which is 40 feet above the ground. The distance from the foot of the ladder to the wall is 9 feet. How long should the ladder be ? 

 A.    9 feet

 B.    81 feet

C.    41 feet

 D.    49 feet

Time and work

1) If 5 women or 8 girls can do a work in 84 days. In how many days can 10 women and 5 girls can do the same work? 

A.    32 days

B.    48 days

C.    52 days

 D.    38 days

Answer : A.

Given that 5 women is equal to 8 girls to complete a work. 
So, 10 women = 16 girls. 
Therefore 10 women + 5 girls = 16 girls + 5 girls = 21 girls.
8 girls can do a work in 84 days then 21 girls can do a work in (8*84/21) = 32 days.
Therefore 10 women and 5 girls can a work in 32 days

2) If 34 men completed 2/5th of a work in 8 days working 9 hours a day. How many more man should be engaged to finish the rest of the work in 6 days working 9 hours a day? 

A.    89

B.    98

 C.    102

 D.    142

Answer : C.

From the above formula i.e (m1*t1/w1) = (m2*t2/w2)
so, (34*8*9/(2/5)) = (x*6*9/(3/5))
so, x = 136 men
number of men to be added to finish the work = 136-34 = 102 men

3) If 9 men working 6 hours a day can do a work in 88 days. Then 6 men working 8 hours a day can do it in how many days? 

A.    89 days

B.    90 days

 C.    85 days

 D.    99 days

Answer : D.
From the above formula i.e (m1*t1/w1) = (m2*t2/w2)
so (9*6*88/1) = (6*8*d/1)
on solving, d = 99 days.

4) A is twice as good a workman as B and together they finish a piece of work in 18 days. In how many days will A alone finish the work? 

A.    31 days

 B.    25 days

 C.    27 days

D.    29 days

Answer : C.

If A takes x days to do a work then B takes 2x days to do the same work.
--> 1/x+1/2x = 1/18
--> 3/2x = 1/18
--> x = 27 days.
Hence, A alone can finish the work in 27 days.

5) Worker A takes 8 hours to do a job. Worker B takes 10 hours to do the same job. How long it take both A & B, working together but independently, to do the same job? 

A.    40/9 days

 B.    40/7 days

C.    7.5 days

D.    8.5 days

Answer : A.
: A's one hour work = 1/8. 
B's one hour work = 1/10. 
(A+B)'s one hour work = 1/8+1/10 = 9/40. 
Both A & B can finish the work in 40/9 days

Quants : Mix Quiz

1.Nitish purchased a TV set for Rs.15,750 after getting 10% discount on the labelled price. He spent Rs.100 on transportation and Rs.850 on installation. At what price should he sell it so that the profit earned would be 15%?
1 : Rs.24045
2 : Rs.23205
3 : Rs.22325
4 : Rs.19205
5 : None of these

2.The compound interest on a certain sum of money at 12% per annum for two years is more than the simple interest on the same sum at the same rate of interest for two years by Rs.8640. Find the sum.
1 : Rs.3 lakh
2 : Rs.12 lakh
3 : Rs.6 lakh
4 : Rs.1.5 lakh
5 : None of these

3.The total age of a large family of 15 members is 420 years. The average age of five elder members is 45 years. The average age of five younger members is nine years. What is the average age of the remaining five members?
1 : 20 years
2 : 25 years
3 : 30 years
4 : 35 years
5 : None of these

Logical Aptitude Questions and Answer

1. When a number is multiplied by 13, it becomes greater to 105 by an amount with which it is lesser to 105 by now. What is the number
15

2. When asked in an exam how much time is left, the teacher answered that the amount of time left is 1/5 of the time already completed. How much time is left
10 minutes

3. Two people were walking in opposite directions.both of them walked 6 miles forward then took right and walked 8 miles.how far is each from starting positions?
10 miles 10 miles

4.Brothers and sisters have I none, but that mans father is my fathers son. Who is that man?
Your son