3. One lap of a standard running track is $400 \mathrm{~m}$.
How many laps does each athlete run in a $5000 \mathrm{~m}$ race?
A 4
B 5
C 8
D 10
E $12 \frac{1}{2}$
3. E The number of laps is $5000 \div 400=50 \div 4=12 \frac{1}{2}$.