$800 \times 5$\%=$40$,  $40$ students at Hamilton Middle School have red hair. 
$5$\% of the students at Hamilton Middle School have red hair. There are $800$ students at Hamilton Middle School. How many students at Hamilton Middle School have red hair? 
a. $$5$$ 
b. $$40$$ 
c. $$400$$ 
d. $$760$$ 