Question

when 9 is subtracted from a number the difference is 13 . therefore the number is ____​

Answer 1

Answer:

number - 9 = 13

number = 13 + 9

number = 22

Answer 2

Answer:

Let the number to be subtracted be a.

So, 13−a,25−a,55−a are in continued proportion.

If a:b::b:c, then we say that a,b,c are in continued proportion, and c is the third proportional of a and b.

Here, b  

2

=ac

=>(25−a)  

2

=(13−a)×(55−a)

a  

2

−50a+625=a  

2

−68a+715

−50a+625=−68a+715

18a=90

a=5

Hence, 5 needs to be subtracted from 13,25,55  such that they are in continued proportion.