Answer:
1. 7 hours
2. No, he will not.
3. 70 Miles/ hour
Explanation:
1. She went 225 miles in 3 hours so divide 225 by 3, you get 75 miles per hour. She needs 300 more miles to complete the trip so multiply 75 miles x 7 hours - 7 hours because she already traveled 3 hours and it takes 4 more hours - and you get 525 Miles, which means she reached her destination.
2. 200 miles divided by 4 hours means he travels at 50M/h. He needs 263M more to complete the journey, and only has 5 hours left. Multiply 50miles x 5 hours, and you will see that it adds up to 450 Miles in 5 hours. He is 13 miles short. Therefore he will not get there in time.
3. Divide 240M by 6 hours. They travel 40M/ h. They need a total of 520 miles, which is now 280 since they already travelled 240M. If you divide 280 miles by 40M/ h, you get 7 hours, but you need 4 hours. Keep bumping it up until you reach 280 miles/ 70 miles per hour. Which will give you 4 hours. Therefore they need to travel at 70m/h to reach their destination within 4 hours.