## anonymous one year ago A car travels 100 meters in 5 seconds. What is the speed of the car? speed = distance over time; 1 mile = 1609 meters

1. anonymous

i need a walk through

2. Michele_Laino

by definition, the speed of the car is: $\Large speed = \frac{{{\text{distance}}}}{{{\text{time}}}}$

3. anonymous

100 miles is distance and

4. anonymous

5 secs is time

5. anonymous

So how much is 100m in miles?? 100/1609 right? :D And how much is 5 seconds in hours? 5/3600 right? :D So miles/hour = $\frac{ 100 }{ 1609 }*\frac{ 3600 }{ 5 }$ 44.7 miles

6. campbell_st

if you multiply both values by 12 you will know how many metres in 1 minute this is because 12 x 5 = 60 then multiply the answer by 60 to find how many metres in 1 hour does that make sense..?

7. Michele_Laino

$\Large speed = \frac{{{\text{distance}}}}{{{\text{time}}}} = \frac{{100}}{5} = ...miles/\sec$

8. anonymous

20

9. Michele_Laino

correct! it is 20 miles/seconds

10. anonymous

????

11. Michele_Laino

we can change unit of measure, namely we can measure that speed in Km/hour

12. anonymous

so 20 is the right answer not what they said?

13. Michele_Laino

20 miles /seconds, is your speed, and as you can see , the corresponding unit of measure is miles/seconds

14. Michele_Laino

nevertheless, if we want to change unit of measure, of course, we get a different answer

15. anonymous

20

16. anonymous

so thats all i had to do

17. anonymous

@Buttercup214 its 20

18. Michele_Laino

yes! if you want the speed in miles/seconds, that is all!

19. anonymous

oh sorry i forgot to say thank you.