Mr Wilson leaves 5 hours before Mrs Wilson. If he averages 75mph and she averages 90mph, how long...

will it take Mrs Wilson to overtake Mr Wilson?

75*5 = 375

That means that mr wilson has traveled 375 miles already before mrs wilson leaves

Mr. Wilson distance = 375 + 75x

Mrs. WIlson distrance = 90x

375 + 75x = 90 x

375 = 90x - 75x

375 = 15x

x = 375/15

x = 25 hours

By the time Mrs Wilson leaves, Mr Wilson has already travelled
5 hours * 75 miles/hr = 375 miles

Mrs Wilson travels 15 miles/hr faster than her husband, so it will take her
375 miles / (15 miles/hr) = 25 hours

Check:

In 25 hrs, Mr Wilson has travelled a further 25 hrs * 75 miles/hr = 1875 miles
for a total of 375 miles + 1875 miles = 2250 miles

In 25 hrs, Mrs Wilson travels 25 hrs * 90 miles/hr = 2250 miles

ok

It seems mr. Wilson really screwed up, when mrs. Wilson found out she decided to chase him down, meaning that she AVERAGED 90 means she was over that half the time, she was really hauling balls. So it seems Mr. Wilson is getting his butt beat in 6 hours.

Your answer is 6

Relative speed = 15 mph

Mr W travels 375 miles before Mrs W leaves

Will overtake after 375 / 15 h = 25 h

PS
I hope they have a few breaks and some sleep !

Before she leaves he travels 5*75 = 375 miles.

The difference between their speeds is 15 mph so it will take
375 miles/15 mph = 25 hr for her to catch up

She won't, because he took a secret offramp that led to his mistress' house. Mrs Wilson drove past the offramp.

75(t+5) = 90t
75t + 375 = 90t
t = 25 hours