Question

The ratio of the sum of my favorite number and 9 to 15 is the same as the ratio of 3 to 5. What is my favorite number?

Answer 1

Let

x---------> my favorite number

we know that

(x+9)/15=3/5------> 5*(x+9)=15*3-----> divide by 5 both sides----> (x+9)=3*3

x+9=9------> x=0

therefore

the answer is

My favorite number is 0