joseph traveled from Boston to Framingham at 50 mph and then back to boston at 40 mph, What was Joseph average speed on the round trip

45 mph

Step-by-step explanation:

the average speed is found by adding the speed together and then divdiing the sum by however many numbers u added together.

So then the average speed would be 50 mph+40mph/2 which equals 45 mph.

d. bc = 12 and ef = 16

step-by-step explanation:

we are given that δabc : δdef such that .

also, it is given that

so, from the options, we need that .

a.

b.

c.  

d.

as, we can see that only option d gives the same ratio as i.e. .

hence, the possible lengths are bc = 12 and ef = 16.