Question 1110674
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1) Car A and car B enter an expressway at the same time and place and head the same direction. Car A travels at 76 miles per hour. 
After 3 hours, car B is 42 miles behind car A. What is the speed of var B?
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In 3 hours, car A traveled the distance of  3*76 = 228 miles.


At this time, car B was 42 miles behind car B. Hence, it traveled 228 - 42 = 186 miles in 3 hours.


Then the average speed of the car B  is  {{{186/3}}} = 62 mph.
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Solved.


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2) After dieting and excersing for several months, Sam now weighs 20% less than he did originally. 
If Sam now weighs 180 pounds, how much did he weigh originally?


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Let x be the Sam's original weight (which is under the question).


Then the problem says that  (1-0.2)*x = 180 pounds,   or   0.8x = 180,


which implies  x = {{{180/0.8}}} = 225 pounds.


It is your answer.
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