Mike is 7.5 miles ahead of julia running at 5.5 miles per hour and julia is running at the speed of 6 miles per hour. how long does it take julia to catch mike.
the answer is 15 hours but i am unsure as to why, can someone explain?

15 hours.

Step-by-step explanation:

Suppose the time taken to catch Mike is t hours and the distance ran by Mike   is x miles then

5.5 = x/ t     (Mike)     --- ...(1)

6 = (x +7.5 )/ t (Julia )(2)

From equation (1):

x = 5.5t  (3).

From equation (2):

x + 7.5 = 6t

x = 6t - 7.5(4).

Eliminating x from equations 3 and 4:

6t - 7.5 = 5.5t

0.5t = 7.5

t = 15 hours.

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step-by-step explanation: