Important Maths Questions with Solution for SSC CGL and CHSL: 31st Jan 2020

Maths Questions with Solution
Que. 1 the sum of three consecutive number is 93. The greatest among these three numbers is
a.         27
b.        28
c.         30
d.        32
Answer d.
Let the three number are x, x+1, and x+2
Then x+(x+1)+(x+2) = 93
3x = 90
x = 30
greater number is = (x+2) =32


Que. 2 The sum of the ages of 4 children born at the interval of 3 year each is 42 years. What is the age of the youngest child?
a.         4 years
b.        6 years
c.         9 years
d.        10 years
Answer b.
Let the age of the youngest child is x years. So the age of other child will be (x+3) ,  (x+6) and (x+9)
x+ (x+3) +(x+6) + ( x+9 ) = 42
4x = 42-18
x = 6
so the age of the youngest child is = 6 years
Que.3  A train moves with the speed of 180 km/hr. find the speed in m/sec?
a.         20 m/sec
b.        30 m/sec
c.         50 m/sec
d.        70 m/sec
Answer c.
180km/hr = 180 X (5/18) = 50 m/sec
Que .4  A can do a work in 4 days and B can do the work in 3 days. How long it will take if both A and B do the work together?
a.         1 days
b.        1 days 5/7 hours
c.         2 days 3 hours
d.        3 days
Answer b.
A’s 1 day work = 1/4 and B’s 1 day’s work = 1/3
So (A + B )’s 1 day’s work = ( 1/4  + 1/3 ) = 7/12
So A and B will finish the work in 12/7 = 1 days and 5/7 hours.
Que . 5 Average age of 6 boys is 12 years. The average age of 4 other boys is 18 years. Find the average age of all 10 boys.
a.         12 years
b.        14.4 years
c.         15.16 years
d.        13 years
Answer b.
Average age of 6 boys = 12 years
So total age of 6 boys = 12 X 6 = 72
Average age of 4 boys = 18 years
So total age of 4 boys = 18 X 4= 72
Total age of 10 boys 72 + 72 = 144
So average age of 10 boys = 14.4 years.

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