Respuesta :

5 hours

First calculate her speed over the first 80 miles

speed = [tex]\frac{distance}{time}[/tex] = [tex]\frac{80}{4}[/tex] = 20 mph

Quadrupling her speed means 4 × 20 = 80mph

time = [tex]\frac{distance}{speed}[/tex] = [tex]\frac{400}{80}[/tex] = 5 hours


ianjharvey07

It will take 5 more hours to drive 400 more miles, because in the first 4 hours she drove a distance of 80 miles(which is 20mph) then, she quadrupled her miles in the next 4 hours and drove a distance of 320 miles(which is 80mph) so she just drove 400 miles, but if she is driving 80 miles per hour it will take 4 hours to drive 320 miles, and 320+80=400, so it will take her 5 more hours to drive 400 more miles.



Please mark brainliest




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