SSC CGL MAINS 2015 : Quant Quiz

1.The average of 7 numbers is 8. If one number is added, their average is 9. Then the added number is

(1) 12   

(2) 11 

(3) 16  

(4) 14

2.With an average speed of 40 km/hr, a train reaches its destination in time. If it goes with an average speed of 35 km/hr, it is late by 15 minutes. The total journey is 

(1) 35 km 

(2) 60 km

(3) 70 km 

(4) 50 km

3.Three students A, B and C play cricket. The runs scored by A and B respectively are in the ratio 3 : 2. B’s runs to C’s runs are also in the same ratio. Together they score 342 runs. Then the runs scored by B are

(1) 216 

(2) 108 

(3) 90  

(4) 171

4.A trader fixes selling prices of commodities after increasing them by 10% and offers 10% 

rebate on selling prices. The per cent. gain or loss is

(1) 1% gain   

(2) 0.9% gain

(3) 1.2% loss  

(4) 1% loss

5.B borrowed Rs. 5,000 from A at 6% p. a. simple interest and lends it to C at compound interest of 10% p. a. If B collects the money back from C after 2 years and repays A, the profit made by B in the transaction is 

(1) Rs.  600 

(2) Rs. 1,050

(3) Rs. 500 

(4) Rs. 450

6.Two trains starting at the same time from two stations 200 km apart and going in opposite directions  cross each other at a distance of 110 Km from one of the stations. The ratio of their speeds is

(1) 11 :20  

(2) 20 :9

(3) 9:20 

(4) 11:9

7.The least number which is divisible by all the natural numbers upto and including 10 is 

(1) 7560  

(2) 1260

(3) 5040 

(4) 2520

8.40 men can finish a work in 15 days. If the work is to be completed 3 days earlier, how many more people should be employed? 

(1) 8  

(2) 10  

(3) 15  

(4) 10

9.A father is 7 years older than the mother and the mother’s age now is 3 times the age of the daughter. The daughter is 10 years old now. What was the father’s age when the daughter was born? 

(1) 27 years 

(2) 37 years 

(3) 15 years 

(4) 40 years 

10.Of the three numbers, the first is twice the second and is half of the third. If the average of these numbers is 56, the numbers in order are. 

(1) 96, 24, 48 

(2) 96, 48, 24 

(3) 48, 96, 24 

(4) 48, 24, 96

ANSWERS AND SOLUTION
1.(3) the added number
= 9 * 8 – 8 * 7
= 72 – 56 = 16

2.(3) If the required distance be x km, then,
x/35 – x/40 = 15/60
= (8x – 7x)/280 = 1/4
= x/280 = 1/4
=> x = 280/4 = 70 km

3.(2) A : B  = 3 : 2 = 9 : 6
B : C = 3 : 2 = 6 : 4
so A : B : C = 9 : 6 : 4
so Runs scored by B = 6/19 * 342
= 108

4.(4) Resultant effect
= (10 – 10 – (10x10)/100)%
= -1%
Negative sings shows loss.

5.(4)
S. I = Principal * Time * Rate / 100
= (5000 * 2 * 6) / 100 = Rs. 600.
C.I = P {(1 + R/100)^t -1 }
= 5000 {(1 + 10/100)^2 -1 }
= 500 (121/100 -1)
= 5000 * 21/ 100
= Rs. 1050
B’s profit = 1050 – 600
= Rs. 450

6.(4) Time is equal
so 110/x = 90/y
=> x/y = 110/90 = 11/9

7.(4) LCM of whole numbers from 1 to 10.
= LCM of 6, 7, 8, 9 and 10
= 2520

8.(4) M1 D1 = M2 D2
=> 40 * 15 = M2 * 12
=> M2 = (40 * 15)/12 = 50
Number of additional men
=> 50 – 40 = 10

9.(1) Mother’s present age
= 30 years
Father’s present age = 37 year
Father’s age 10 years ago
= 37 – 10 = 27 years

10.(4) Second number = x (let)
First number = 2x
Third number = 4x
so x  + 2x + 4x = 56 * 3
=> 7x = 56 * 3
x = 8 * 3 = 24
Other numbers are : 48 and 96