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At the end of spring break, Mary left the beach and drove back towards home, driving at a rate of 51 mph. A friend of Mary left the beach for home 0.5 hour later, and drove 66 mph. How long did it take Mary's friend to catch up to Mary?

Respuesta :

jcherry99

Answer:

2.2 hours or

2 hours and 12 minutes they will meet.

Step-by-step explanation:

Givens

Mary's speed = 51 mph

Friend's speed = 66 mph

Mary will be on the road for t hours

Her Friend will be on the road t - 0.5. Why minus? Because she was on the road 1/2 hour less than Mary was. Any time you see More or Less in a question, pay attention. usually it is the key to the question.

Equation

d_Mary = d_friend

d = rate * time

Solution

51 * t = 66*(t - 0.5)                 Remove the brackets.

51*t = 66*t - 66*0.5

51*t = 66*t - 33                    Subtract 66t from both sides. Be careful

51t - 66t = - 33                     Combine

- 15t = - 33                            Divide by - 15

t = - 33/-15

t = 2.2 hours or 2 hours and 12 minutues

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