$1-20$\%=$80$\%,  $60 \times 80$\%=$48$.  $48$ bananas are in good condition. 
In a basket, there are $60$ bananas. $20$\% of them are rotten. How many bananas are in good condition? 
Options:
a. $$12$$ 
b. $$20$$ 
c. $$48$$ 
d. $$60$$ 