Question

Two numbers are such that the ratio between them is 9:11. If the first number is decreased by 1 and the
second number is increased by 1, the ratio between the new numbers so formed is 7:9. Find the original
numbers.​

Answer 1

Let the two numbers be x,y

y

x

=

5

3

⇒x=

5

3

y

y+10

x+10

=

7

5

=7x+70=5y+50

=7x+20=5y

=7x+20=5y=0

=7(

5

3

)y+20−5y=0

=21y+100−25y=0

=100−4y=0

=100=4y

∴y=25

x=

5

3

×25=15

Thus numbers are 15,25