From the beginning we know we are dealing with two different rates. Distance is equal to (Speed X Time). We have two different speeds though. We will call the min speed = x and the max speed = y. With those two ideas in place we can make two equations for both Tony and Rae.
Tony:
2x+3.5y=355
Rae:
2x+3y=320
Now you can solve the equations by subtracting Rae's equation from Tony's
.5y=35 solve for y and you get 70
Now plug that y value back into either equation and you can solve for x. I'll use Rae's distance:
2x+3(70)=320
x=55
6 seashells left is the answer
ln 5
e = ?
x
Keep in mind that y=e and y = ln x are inverse functions of one another.
ln 5
e , we can drop both the "e" and the "ln 5." We are left with 5 (answer).
ln 5
Alternatively, we could take the ln of both sides of y = e
which will result in ln y = (ln 5) ln e. Note that ln e = 1 (these two functions are inverses of one another).
Then we are left with ln y = ln 5. Dropping the "ln" operator from both sides,
y=5 (same as before).
Answer:
about $2.54 per pound of sugar