# Can anyone solve this question

#### lev888

##### Senior Member
What are the formulas for the 3 average speeds?

#### HallsofIvy

##### Elite Member
Going a distance d miles at x miles per hour takess d/x hours. Going a distance d at y miles per hour takes d/y hours.
So the total trip, 2d miles, required d/x+ d/y= d(x+ y)/xy hours. The average speed for the entiire trip was "distance divided by time"= 2d/[d(x+y)/xy]= 2xy/(x+ y) miles per hour. We are told that is 50 miles per hour so have 2xy/(x+ y)= 50. xy/(x+ y)= 25. xy= 25(x+ y)= 25x+ 25y. xy- 25y= y(x- 25)= 25x. y= 25x/(x- 25). Mathematically x can be any number except 25 miles per hour. Practically, there are limits as to how fast he can go and, of course, x cannot be negative.

#### Laksh13

##### New member
Hallsoflvy can you please do the whole question

#### Subhotosh Khan

##### Super Moderator
Staff member
Let provided asked you very important, yet simple question - you didn't answer that.

Prof Ivey gave you fairly detailed instructions - you do not follow those.

When are YOU going to do and show YOUR work!!!!

#### Laksh13

##### New member
Let provided asked you very important, yet simple question - you didn't answer that.

Prof Ivey have you fairly detailed instructions - you do not follow those.

When are YOU going to do and show YOUR work!!!!
Can you send me the whole answer in document form if possible, I will try to understand from that

Last edited by a moderator:

#### Subhotosh Khan

##### Super Moderator
Staff member
Can you send me the whole answer in document form if possible, I will try to understand from that
No - I will not provide complete answer prior to YOU showing YOUR work.