MENU
Question -

The difference of the squares of two positive integers is 180. The square of the smaller number is 8 times the larger, find the numbers. [CBSE 2014]



Answer -

Let first large number = x
and smaller number = y
According to the condition,
x2 – y2 = 180 …(i)
and y2 = 8x
From (i) and (ii),
x2 – 8x – 180 = 0
=> x2 – 18x + 10x – 180 = 0
=> x (x – 18)+ 10 (x – 18) = 0
=> (x – 18) (x + 10) = 0
Either x – 18 = 0, then x = 18
or x + 10 = 0, then x = -10 But it is not possible being negative
x = 18
First number =18
Then second number y2 = 8x
y2 = 8 x 18 = 144 = (12)2
=> y = 12
Numbers are 18, 12

Comment(S)

Show all Coment

Leave a Comment

Free - Previous Years Question Papers
Any questions? Ask us!
×