HELP ME! Explain how you could use the dimensions of a reduced rectangle and one given measurement of an original rectangle to find a missing measure?

ruth is 6 years old

step-by-step explanation:

6 + 24 = 30,   so 6/30 = .2  

if you do 1/5 it also equals .2, so that is the answer.

i think it might be a but you might want a second opinion