Correct

丰富 vs 多

/ fēngfù vs duō /
Strokes

Formula

1
情节丰富 (rich and colorful plots)
2
感情丰富 (emotional)
3
多才多艺 (versatile)
4
多谋善断 (wise and resourceful)
5
经验丰富 (rich experience)
6
知识丰富 (knowledgeability)
7
内容丰富 (rich content)

Definition

丰富 and 多 both as Adjectives or Verbs, which means [abundant; enrich; many; exceed].

 

Example

丰富 and 多 both as Adjectives, mean "large quantity".
1) However, 丰富 mainly stresses abundance and extensiveness, mostly applied to products, knowledge, experience, programs, etc., whereas 多 is usually applied to ordinary things.

2) In the two examples, example ① is about extensive knowledge, so 丰富 is used; example ② is about people, so 多 is used. 丰富 and 多 are not interchangeable in these two sentences.
1
xuéshí
学识
fēng
丰富
  
,
tán
谈吐
yōu
优雅
  

He is knowledgeable and talks with clegance.

2
Jīntiān
今天
lái
de
rén
hěn
duō
  

There are many people present here.

In other situations concerning abstract things such as 情节丰富 (rich and colorful plots), 感情丰富 (emotional), etc. 多 cannot be used either.
情节丰富 (rich and colorful plots) 感情丰富 (emotional)
3
yǒu
fēng
丰富
de
xiǎngxiàng
想像力
  

She has plenty of imagination.

Even when applied to "things", 丰富 is used for those more abstract things like 物产 and 多 is used for those more concrete things, such as 粮食,木材.
4
Zhè
这里
yǒu
fēng
丰富
de
kuàngchǎn
矿产
  

The area is rich in minerals.

5
Liángshi
粮食
duō
le
  
,
jiù
zhíde
值得
zhēn
珍惜
le
ma
  
?

Can't we treasure them if we have plenty of foods?

丰富 has a commendatory sense, while 多 is neutral.
eg, the meaning of 经验丰富 (rich experience) is commendatory, and that of 经验多 is neutral. 多 is used in the sentence below because it means "inadequate knowledge", and 丰富 is not used.
6
tiānwén
天文
fāngmiàn
方面
de
zhīshi
知识
duō
  

I know a little about astronomy.

If there is a commendatory sense, even if an inadequate quantity, 丰富 should be used.
However, there are some set phrases,e.g. 多才多艺 (versatile), 多谋善断 (wise and resourceful), etc. where 丰富 is not used.
多才多艺 (versatile) 多谋善断 (wise and resourceful)
7
Zhège
这个
xuésheng
学生
zài
shǐ
历史
fāngmiàn
方面
de
zhīshi
知识
hái
gòu
不够
fēng
丰富
  
,
dàn
běn
基本
zhīshi
知识
háishi
还是
yǒude
有的
  

The student does not know history well,but he knows its ABC.

多 can function as a complement of adjectives or certain phrases to indicate a high degree; 丰富 cannot be so used.
8
Jīng
jiǎng
  
,
míngbai
明白
duō
le
  

I understand it better after his explanation.

9
qián
以前
dǒngshì
懂事
duō
le
  

He is more reasonable than he was.

多 can also function as a complement of result to indicate an excess; 丰富 cannot be so used.
10
jīntiān
今天
jiǔ
喝酒
duō
le
  

He drank more wine than is necessary today.

11
Jiāshuǐ
加水
jiāduō
加多
le
  
,
chá
tài
dàn
le
  

The tea was weak for it was added to too much water.

多 as an Adverbial means more than with numbers and measure words used correspondingly; 丰富 cannot be so used.
12
Zhège
这个
yuè
shàngyuè
上个月
duō
shōu
收入
500
500
yuán
  

The income of this month is five hundred yuan more than that of last month.

13
Zuò
zhèxiē
这些
shùxué
数学题
  
,
duō
yòng
le
bàn
ge
xiǎoshí
小时
  

It took me half an hour more than you to finish the math questions.

多 as a Verb, means "more than necessary or superfluous".
As a Verb, 多 and 丰富 are not interchangeable.
14
Zhè
这里
duō
le
ge
  
,
shān
删去
  
!

There are a few unnecessary words here. Please leave them out.

15
shǔ
guò
le
  
,
gòng
一共
10
10
zhī
qiān
铅笔
  
,
zěnme
怎么
duō
chū
le
1
1
zhī
  
?

I have counted and there are ten pencils in all. Why is there eleven ones?

16
Zhè
这里
méi
de
shì
  
,
duō
shénme
什么
zuǐ
  
?

You have nothing to do with it. Why do you poke your nose into it?

丰富 as a Verb means "to enrich" and the object is usually 经验 (experience), 知识 (knowledge), 内容 (content), etc.
As a Verb, 多 and 丰富 are not interchangeable.
经验丰富 (rich experience) 知识丰富 (knowledgeability) 内容丰富 (rich content)
17
Zhè
běn
shū
  
,
大大
fēng
丰富
le
de
zhīshi
知识
  

Reading the enriched me.

18
Wèile
为了
fēng
丰富
自己
de
课余
shēnghuó
生活
  
,
cānjiā
参加
le
xiē
一些
wài
课外
huódòng
活动
  

She takes part in some extracurricular activities to enrich her spare time.