Important Maths Questions for SSC CGL Exam

Important Maths questions for SSC CGL Exam

11.  The square root of (0.75)3 /1-0.75 + [0.75 + 90.75)2 +1] is-

a.   1

b.   2

c.   3

d.   4

12.  Given that √4096 = 64, the value of √4096 + √40.96 +√0.004096 is-

a. 70.4
b. 70.464
c. 71.104
d. 71.4

13.  By selling an article at 3/4th of the marked price, there is a gain of 25%. The ratio of the marked price and the cost price is-

a.   5 : 3

b.   3 : 5

c.   3 : 4

d.   4 : 3

We know  S.P. = Rs.3x/4

and C.P. = 3x/4 * 100/125

= Rs.3x/5

We know  required ratio = x: 3x/5

= 5:3

14.  A and B earn in the ratio 2:1. They spend in the ratio 5:3 and save in the ratio 4:1. If the total monthly savings of both A and B are Rs.5,000, the monthly income of B is-

a.   Rs.7,000

b.   Rs.14,000

c.   Rs.5,000

d.   Rs.10,000

We know   Monthly income of A = Rs. 2x and

Saving of A =5000 * 4/(4 + 1)

= Rs. 4000

Saving of B = Rs.1000

We know that 2x – 4000/x-1000 = 5/3

=>  6x – 12000 = 5x – 5000

We know   x = Rs.7000 

15.  The ratio of the sum of two numbers and their difference is 5:1. The ratio of the greater number to the smaller number is-

a.   2 : 3

b.   3 : 2

c.   5 : 1

d.   1 : 5

We know that x + y/ x – y = 5/1

=>  5x – 5y = x + y

=>  4x = 6y

=>  x/y = 6/4

x : y = 3 : 2 

16.  A cistern has 3 pipes A, B and C. A and B can fill it in 3 and 4 hours respectively, and C can empty it in 1 hour. If the pipes are opened at 3 p.m., 4 p.m. and 5 p.m. respectively on the same day, the cistern will be empty at-

a.   7.12 p.m.

b.   7.15 p.m.

c.   7.10 p.m.

d.   7.18 p.m.

We know that x -3/3 + x – 4/4 = x – 5/1

=>  4x – 12 + 3x – 12/12 = x – 5/1

=>  7x – 24 = 12x – 60

=>  5x = 36

We know   x = 36/5

= 7 hr. + 12 min.

= 7.12 p.m.

17.  If A works alone, he would take 4 days more to complete the job than if both A and B worked together. If B worked alone, he would take 16 days more to complete the job than if A and B work together. How many days would they take to complete the work if both of them worked together?

a.   10 days

b.   12 days

c.   6 days

d.   8 days

Let x days are taken when they work together.

We know   Time taken by A to complete the work = (x + 4) days

And Time taken by B to complete the work = (x + 16) days

We know that 1/x = 1/x + 4 + 1/x + 16

We know   1/x = x + 16 + x + 4/(x + 4) (x +16)

We know   2×2 + 20x = x2 + 20x +64

We know   x2 = 64 (8)2

We know   x = 8 days  

18.  250 men can finish a work in 20 days working 5 hours a day. To finish the work within 10 days working 8 hours a day, the minimum number of men required is-

a.   310

b.   300

c.   313

d.   312

=312.5

313 

19.  2 men and 5 women can do a work in 12 days. 5 men 2 women can do that work in 9 days. Only 3 women can finish the same work in-

a.   36 days

b.   21 days

c.   30 days

d.   42 days

We know that (2m + 5w) * 12 = (5m + 2w) * 9

=>  24m + 60w = 45m + 18w

=>  21m = 42w

=>  1m = 2w

We know   2m + 5w = 9w

We know   required no. of days = 9 * 12/3

= 36 

20.  While selling, a businessman allows 40% discount on the marked price and there is a loss of 30%. If it is sold at the marked price, profit per cent will be –

a.   10%

b.   20%

c.   16 2/3%

d.   16 1/3%