Which of the following fractions is equivalent to 3/8?
a.6/14
b.9/24
c.4/9
d.15/35

I'm going to suggest that we take these and "UN-simplify" them.

For each choice, divide the numerator by 3 and the denominator by 8.

Look at this:

A).  6/14

      6 ÷ 3 = 2  
    14 ÷ 8 = 1.875      ===>  2/1.875     not interesting

B).  skip B for just a second

C).  4/9

       4 ÷ 3 = 1.33
       9 ÷ 8 = 1.125        ===>  1.33/1.125    not interesting

D).  15/35

       15 ÷ 3 = 5
       35 ÷ 8 = 4.375    ===>   5/4.375         not interesting

But now look at choice-B:

B).  9/24

       9 ÷ 3 = 3
     24 ÷ 8 = 3        ===>  1/1    interesting !

-- To simplify  9/24, the top and bottom were divided by 3, giving 3/8.

-- To UN-simplify  3/8, the top and bottom were multiplied by 3, giving 9/24.

-- Choice-B  is the one that's equivalent to 3/8.


OK.  All of that wasn't really necessary.
All you really need to do is take each choice and simplify it.

A).  6/14
       Divide top and bottom by 2  ===>  3/7

B).  9/24
       Divide top and bottom by 3  ===>  3/8 

C).  4/9
       Can't be simplified.  Already in simplest form.

D). 15/35
     Divide top and bottom by 5  ===>  3/7