Question 196602
Commuting students. At a well-known university, 1/4 of the undergraduates
 commute; 1/3 of the graduates commute. 1/10 of the undergraduates drive more
 than 40 miles daily and 1/6 of the graduates drive more than 40 miles daily.
 If there are twice as many undergrads as there are grad students,
 then what fraction of the commuters drive more than 40 miles daily?
:
Let's use a convenient number for the total students: 720 has a lot of factors
:
It says,"there are twice as many undergrads as there are grad students,"
That would give us us 480 undergrads, and 240 grads for a total of 720
:
1/4 of the undergraduates commute; 
{{{1/4}}} * 480 = 120 
:
1/3 of the graduates commute.
{{{1/3}}} * 240 = 80
:
1/10 of the undergraduates drive more than 40 miles daily
{{{1/10}}} * 480 = 48
: 
1/6 of the graduates drive more than 40 miles daily.
{{{1/6}}} * 240 = 40
:
what fraction of the commuters drive more than 40 miles daily?
Total commuters: 120 + 80 = 200 
Total commuters drive more than 40 mi: 48 + 40 = 88
:
Then: {{{88/200}}} = {{{11/25}}} of the commuters commute over 40 mi