Question 404852
Let {{{t}}} = time to drive yesterday
{{{t + 16}}} = today's time
{{{t - 5}}} = time he wants to drive tomorrow
The average time is:
{{{(t + t + 16 + t - 5)/3 <= 30}}}
{{{(3t + 11)/3 <= 30}}}
{{{ 3t + 11 <= 90}}}
{{{3t <= 79}}}
{{{t <= 79/3}}}
{{{t + 16 <= 127/3}}}
{{{t - 5 <= 64/3}}}
The times are:
26 1/3 min, 42 1/3 min, and 21 1/3 min