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:
[tex]3=\frac{45}{x+8}+\frac{60}{x}[/tex]And we can solve for x and we got:
[tex]3=\frac{45x+60x+480}{x^2+8x}[/tex][tex]3x^2+24x=105x+480[/tex][tex]3x^2-81x-480=0[/tex]then solving for x we got:
x= 32
The answer would be : 32 mph