[Grammar] rs, r's and rs'

[joaost]

Please help me understand when to end words with rs, r's and rs'.

For example:
"The customer's first purchase has a discount." --> is this correct?
"The customers' are our livelihood." --> is this correct?

Please give me some examples, I am never sure how to write this.

Thank you in advance,
JT

 

[Rover_KE]

Welcome to the forum, JT.

The customers are our livelihood. Simple plural—no apostrophe.

The customer's baby fell out of her pram. Singular possessive—one customer.

The customers' bags burst open when they left the store. ​Plural possessive—more than one customer.

 

[TheParser]

***** NOT A TEACHER *****

1. "The teachers at my school work very hard." (There are 50 teachers.)

2. "The teacher's students love her." (The students of the teacher.)

3. "All of the teachers' cars are inexpensive." (The cars of the 50 teachers.)