So, Mary Lou took[tex] \frac{5}{6} [/tex] of an hour, that is [tex] \frac{5}{6}*60 mins=50 mins [/tex]
Heather took [tex] \frac{9}{10} [/tex] as much time as Mary Lou, so she took [tex] \frac{9}{10} [/tex] of 50 minutes, that is [tex] \frac{9}{10}*50=45 [/tex]
45 minutes is less than 50, so Heather was faster and Mary Lou was slower and took longer!
