Trying to add .1 to whole row automatically. Please Help!

Hi! I am in desperate need to figuring out how to put a formula into a row (.1 per number into the row automatically). For example:

So if I have 5 clients
.1 per client needs to be added per client.
= .5 per hour

So, for 3 hours if there was 5 clients...
3 hrs. x .5 per hour = 1.5
1.5 + 3 hrs. = 4.5

Basically, I want for each client that is on the row, I want .1 added to it automatically. For example, if I have 7 clients in C3, .7 should be added to it automatically.

Please help!
Thank you!

This is a daily thing unfortunately, I should have been clearer. (Sorry! -_-) I put a number in A1 and only A1 has to have .1 added to each whole number. (Ex. 5 clients = .5) I want this to be autofilled everytime I put a number in.

This is what I am currently working on. Highlighted in red is all I care about for now. For each whole number (Example: 5 clients = .5 and 1 client = .1) is what I am trying to do so it adds up with the billable hours and the totals. The main objective is how do I put .1 automatically when I have a another whole number? (Client in this case.)

Try this =SUMIF($A$6:$A$23;"Clients";B$6:B$26) put in B3, it add up when you input value on Client
Is this what you mention? Sorry I'm still confused....

1 client = .1
5 clients = .5
10 clients = 1

For each client is a .1

Mon. Tues. Thurs. is 3 hours a day
Only Wed. is 2 hours a day

Main objective is to get the clients to automatically have the .1 added when entering clients to calculate hours a day for group sessions

For example, if 5 clients come in on Monday, it would be 3 hours on a Monday

5 clients x .1 per person = .5 per hour
then x 3 hrs .5 = 1.5
take the 1.5 + 3 hours= 4.5 hours

If B3 = clients and B4 = hours
then you need
=(1+A3/10)*B4