Answer:
7
Explanation:
4+9+7+8+7=35, 35/5=7 (mean)
most common number=7 (mode)
4, 7, 7, 8, 9; center number is 7 (median)
I figured this out by guessing and checking. Because it has to be a mode, your options are restricted to the numbers provided in the set. 7 was in the middle so its where I started and it worked first try.