Question

9. (-15 Points]DETAILSMY NOTESASK YOUR TEACHERNancy took a 3 hour drive. She went 45 miles before she got caught in a storm. Then she drove 60 miles at 8 mph less than she had driven when the weather was good. What was herspeed, in miles per hour, driving in the storm?mph

Answer 1

Solution

We can use the following formula:

v= d/t

where v= velocity, d= distance, t= time

Nacy speed in good weather is:

x+ 8 mph

the speed of Nancy in storm will be x mph

The time taken to drive 45 mi in good weather is:

t1= 45/(x+8)

The time to drive 60 mi in storm is:

t2= 60/x

The total time is 3hr so we have:

$3=\frac{45}{x+8}+\frac{60}{x}$

And we can solve for x and we got:

$3=\frac{45x+60x+480}{x^2+8x}$$3x^2+24x=105x+480$$3x^2-81x-480=0$

then solving for x we got:

x= 32

The answer would be : 32 mph