Question

Calculate the average speed (in km/h) of Larry, who runs to the store 4.6 kilometers away in 24 minutes.

Answer 1

I know that Average Speed= total distance covered/time interval
So I do 4.6/24 and get 0.1916666667

Answer 2

yes, but that is km/min

Answer 3

So how do I do km/h?

Answer 4

60 min / 1 hour
do this:
\[0.1916666667 \frac{km}{\cancel{min}} \cdot \frac{60 \ \cancel{min}}{hour} = ? \]

Answer 5

Okay I cross multiplied and got 11.5

Answer 6

or you could first change 24 minutes to hours doing
\[ 24 \ \cancel{min} \cdot \frac{1 \ hour}{60\ \cancel{min}} = 0.4\ hours\]
then do
\[ \frac{4.6 \ km}{0.4 \ hrs} \]

Answer 7

Right, but when I put in 11.5 km/h it says its wrong. it says "Not quite. Check through your calculations; you may have made a rounding error or used the wrong number of significant figures."

Answer 8

maybe it just wants 11.50
?

Answer 9

Nope. :/

Answer 10

the only other thing I can think of, is it want only 2 significant digits, which would mean 12

Answer 11

There's a space for value which is where I put 11.5 and then there's a space for unit which is where I put km/h

Answer 12

can you post a screen shot ?

Answer 13

Yes one second

Answer 14

btw, did you try 12 km/h ?

Answer 15

I didn't even think to round up, yes it worked lol. Thanks!