Let Jean's speed while running = x mph
Then Jean's speed while riding will be = x+9 mph
Distance covered by running = 8 miles
Distance covered by riding = 11 miles
Total time taken to complete the race = 1.5 hours
As, 
So, time for running= 
And time for riding= 
Equation becomes:

Now, multiply every term by 2x(x+9) to clear denominators:

Simplifying it we get

Solve the quadratic equation using formula

putting a=3 , b= -11, c= -144
we get (x - 9)(3x + 16) = 0
where x=9 and x=
Neglect the negative answer as speed cannot be negative, so x = 9 mph
Hence, Jean's running speed is 9 mph and riding speed is x+9 = 9+9 = 18 mph
Answer:
A
Step-by-step explanation:



This option works
9514 1404 393
Answer:
x = 8 1/3
Step-by-step explanation:
Put the known values into the equation and solve for x.
f(x) = 3x -1
24 = 3x -1 . . . . . use 24 for f(x)
25 = 3x . . . . . . . add 1 to both sides
25/3 = x . . . . . . divide both sides by 3
The input is x = 8 1/3.
A= bh(1/2)
a=12(14)(1/2)
a= 168(1/2)
a= 84inches