Number System in math for Competitive examination Part 1 Specially SSC CGL Bank Rail TET exam

Here is some questions and answers on Simplification

Q.1 The Sum of all those prime nos which are not greater than 17 is ....a)59 b)58 c) 41 d) 42


Ans. Prime no till 17 are 2,3,5,7,11,13,17
Required sum =2+3+5+7+11+13+17=58

Q.2 The sum of a natural no and its square equals the product of the first three prime nos. What is the number?


Ans. Let the required no be x
According to the question
x^2+x=2×3×5
or x^2+x-30=0
or (x-5)(x-6)=0
Therefore x=5


Q.3 Out of six consecutive natural numbers ,if the Sum of first three is 27, what is the sum of other three?


Ans. Let the three consecutive natural numbers be x,x+1,x+2
According to the question ,
x+x+1+x+2=27
or 3x+3=27
or x=8

First three consecutive nos 8, 9, 10

Therefore sum of next 3 consecutive nos
=11+12+13
=36