Question 305397
After 20 minutes (1/3 hr), the Smiths have a 16 mile lead. 
Rate*Time=Distance
{{{48*t+16=60*t}}}
{{{12t=16}}}
{{{t=16/12=4/3}}}
They overtake them in 4/3 hours or 1 hr 20 minutes after they leave.
It would then be 9:40.