Question 1007225

I came up with 30mi....but I can't really explain how I got it. Tom Quig traveled 210 miles east of St. Louis. For most of the trip he averaged 60 mph, but for one period of time he was slowed to 10 mph due to a major accident. If the total time of travel was 6 hours, how many miles did he drive at the reduced speed?
<pre>Let distance at reduced speed (10 mph) be D
Then distance traveled at 60 mph = 210 – D
Time traveled at 10 mph: {{{D/10}}}
Time traveled at 60 mph: {{{(210 - D)/60}}}
We then get: {{{D/10 + (210 - D)/60 = 6}}}
6D + 210 – D = 360 --------- Multiplying by LCD, 60
6D – D = 360 – 210
5D = 150
D, or distance covered at reduced speed (10 mph) = {{{150/5}}}, or {{{highlight_green(30)}}} miles