The answer is 27 because the are nine options which can be recombined in 3 independent ways. Therefore, 9*3=27
If Teresa drove 936 miles in 13 hours, this would mean she would have driven 72 miles every hour. 72 times 9 equals 648. After 9 hours, she would have driven 648 miles.
X should be 3,
because 8x means 8 times what number.
So 8x must be 3.
8 times 3 = 24. 24 +5 = 29.
Hope you Understand :) !