Question 1163732
Allison drove home at 62 mph, but her brother Austin, who left at the same time , could drive at only 42 mph.
 When Allison arrived , Austin still had 40 miles to go,
 How far did Allison drive ?
:
let d = distance A drove (home)
time = d/speed
:
{{{d/62}}} = {{{(d-40)/42}}}
cross multiply
62(d-40) = 42d
62d - 2480 = 42d
62d - 42d = 2480
20d = 2480
d = 2480
d = 124 mi the dist A drove home