SSC CGL Tier II 12 Jan 2017 Paper 1

Question : 1 of 100

Marks: +1, -0

QUANTITATIVE ABILITIES

Twenty one times of a positive number is less than its square by 100. The value of the positive number is

Solution:

(1) Suppose, the positive number be x.
According to the question,

x^{2}-21 x=100

⇒ x^{2}-21 x-100=0

⇒ x^{2}-25 x+4 x-100=0

⇒ x(x-25)+4(x-25)=0

⇒(x-25)(x+4)=0

⇒ x=25

because

x ≠-4

Go to Question:

Next Question