What does this mean, espacially 块, 分 and 毛 in this sentence?
一斤香蕉多少钱？两块七毛五分一斤，五块钱两斤

I don't know how to understand the answer.
I know that 毛 is 1/10 od yuan, and 分 is 1/100 of yuan. And I fond the information that 块 = 10 jiao. But what the heck is 10 jiao? And how is the jiao related to the yuan?

Thanks for answering!

Question

What does this mean, espacially 块, 分 and 毛 in this sentence?
一斤香蕉多少钱？两块七毛五分一斤， 五块钱两斤

I don't know how to understand the answer. 
I know that 毛 is 1/10 od yuan, and 分 is 1/100 of yuan. And I fond the information that 块 = 10 jiao. But what the heck is 10 jiao? And how is the jiao related to the yuan?

Thanks for answering!

Answer

1元（块）=10角（毛）
1角（毛）=10分

元 and 快 are same.
角 and 毛 are same too.
just some different way to call it.

Answer

1块=1元=10毛=10角=100分，现在分的面值已经不发放了，口语中块和毛用得都比元和角多。现在台湾的的最小面值是1元

Answer

I didn't understand all that Anita wrote, but thank you both! :)

Answer

清稗類鈔  徐珂（１８６９～１９２８）編撰。民國六（１９１７）年商務印書館初版。 方言類 廣州方言 : 銀紙，鈔票也。毫子，小銀元也。仙，銅元也。一文，一塊銀元呼作一文，【音作蚊。】惟一元幾角，即不作一文幾毛，而曰一個幾毫，整數用文，零數即作個也。  
方言類 上海方言 : 溫大拉，銀元一枚也。考其源，實出於英文之One Dollar，販夫走卒咸解之。四開，兩角之小銀元也，粵語謂之雙毫。金四開，英幣之鎊也，以其大小與四開相等，乃有此稱。銅四開，銅元也，猶杭州人謂之銅板，江北人謂之銅角子，北方謂之銅子也。銅生斯，即銅四開也，其源出於英文之Cent，即一分也，值一分之銅幣也。八開，一角之小銀元也，京語謂之小毛錢，粵語謂之毫子。

Answer

1元=1块
1角=1毛
1元=10角
1角=10分
1元=100分
只是不同说法而已，牢记下就可以。分现在在中国很少用到了，只有极其少的地方会用到。