To figure this out, you have to figure out what Donovan scored.
Just divide his score (39 ÷ 50) and get 0.78.
Since we already knew this, we can figure out Marci's score. Since she score 88%, we can assume she scored somewhere in the 40's.
Once you figure out what her score was out of 50, divide it.
Your equation should look like this: 44 ÷ 50 = 0.88
This means that Marci answered 44 questions out of 50 questions correctly. (44/50)