Homework help please !?
i need help. you have to write and algebraic model:
A car travels at an average speed of 45 miles per hour for 8 miles, reduces its speed by 15 miles per hour for the next 4 miles, and then returns to a speed of 45 miles per hour. how long does the car travel at the reduced speed. CAN SOMEONE EXPLAIN PLS ?
- CarrotLv 51 decade agoFavorite Answer
The car doesn't go 15 miles for the next 4 miles, it reduces its speed by 15 miles, which leaves it at 30 mph.
30 mph = 30 miles/60 min = 1 mile/ 2 min
He goes 4 miles, which means that he was traveling at that speed for 8 minutes. (4 miles * 2 min/mile = 8 minutes)
- 1 decade ago
We only need the original 45mph from the first part of the question to tell us our original speed. So, when you reduce your speed by 15mph you get
45mph - 15 mph = 30mph
The next part I would do as a ratio because it is simpler that way.
1. Change 1hr to 60 min
2. Compare 30mi/60min -->this is your rate or speed -- to
3. Miles driven, 4mi.
Your ratio will look like:
30 mi/ 60 min = 4mi/ x min
1. Cross multiply
30mi * x min = 60min *4mi
2. 30x = 240 -- some teachers want the units, some don't
3. Divide both sides by 30 and ...
x = 8min
- olliLv 44 years ago
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