Question

Calculate the average speed for each of the following.

126 km in 2 1/4 h. ________________
292 1/2 km in 4 1/2 h. ________________
288 km in 3 3/5 h. _____________________

Can someone provide the answer and explain how you got the answer so I understand?

Answer 1

your job in each of these is to divide

Answer 2

so for the first one you need
\[126\div 2\tfrac{1}{4}\]

Answer 3

and if you want to divide, you need to take that stupid mixed number and turn it in to an improper faction. so
\[2\tfrac{1}{4}=\frac{2\times 4+1}{4}=\frac{9}{4}\]

Answer 4

you divide by a fraction by multiplying by the reciprocal, so the first problem is solve by writing
\[126\div \frac{9}{4}=126\times \frac{4}{9}=14\times 4=56\]

Answer 5

second two are similar. try them and if you can't get them ask

Answer 6

Thanks a lot :D