Need help on this exam

If you are just building your payment history, how many points from a perfect score will you possibly miss?

Table which ratio is equivalent to 3: 7? 6: 7 3: 21 24: 56 15: 30

Atourist boat is used for sightseeing in a nearby river. the boat travels 2.4 miles downstream and in the same amount of time, it travels 1.8 miles upstream. if the boat travels at an average speed of 21 miles per hour in the still water, find the current of the river.