如图是科特迪瓦农矿产品及城市分布图，读图回答问题。
—Have you heard of the good fireman, Quan Zhanrong?—Yes, he thought of others ______ than himself.
奶奶养的黑兔比白兔少百分之二十．写出这个百分数是____％，并写出黑兔只数是白兔的____％．
