what is the missing number which makes the fractions equivalent 3 15

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5 ?

multiply by 3/3 and you have

3/5 * 3/3 = 9/15

yes I know but that is not on my quiz... so that why I came here.

what does it matter whether it was on a quiz? It's just a math problem. Is there something unsatisfactory with my response?

What is the missin number 4/7=8/

3/5=15/3