Hello!
The drive from San Antonio to Houston is 3 1/3 hours
The drive from Houston to Dallas is 4 1/12 hours
You have to add these but first you have to make the denominators of the fractions the same
1/3 = 4/12
3 4/12 + 4 1/12 = 7 5/12
The answer is B) 7 5/12 hours
Hope this helps!