Let's first find the speed Sue can run at in miles per hour.
Sue runs 1/6 mile in 1/10 hour.
To find the speed (the unit rate) we divide the distance by the time.
Sue's speed = (1/6 mile)/(1/10 hour) = 1/6 * 10/1 miles/hour = 10/6 miles/hour = 5/3 miles/hour
Bill's speed is 1/4 of Sue's speed, so we divide Sue's speed by 4 to find Bill's speed.
Bill's speed = (5/3 mph)/4 = (5/3 mph) * 1/4 = 5/12 mph
Bill's speed is 5/12 miles per hour.
Bill can run 5/12 of a mile in an hour.
30 minutes is half an hour, so in half an hour, he runs half of 5/12 of a mile.
Answer: Bill can run 5/24 of a mile in 30 minutes.