Answer:
4 hours
Step-by-step explanation:
Since we know he travels at a rate of 1:7.5 all we have to do is divide 7.5 by 30. Do you use proportions? You can set this up as a proportion and the find answer easily.
1
Now we cross product.
7.5 multipled by x =7.5x
1x30=30
so now we have
7.5x=30
Now we have to divide 7.5 on both sides which gives us
x=4