Answer:
a. 
b. 
c. 
d. 
Step-by-step explanation:
Given that there are two laptop machines and four desktop machines.
On a day, 2 computers to be set up.
To find:
a. probability that both selected setups are for laptop computers?
b. probability that both selected setups are desktop machines?
c. probability that at least one selected setup is for a desktop computer?
d. probability that at least one computer of each type is chosen for setup?
Solution:
Formula for probability of an event E can be observed as:

a. Favorable cases for Both the laptops to be selected =
= 1
Total number of cases = 15
Required probability is
.
b. Favorable cases for both the desktop machines selected = 
Total number of cases = 15
Required probability is
.
c. At least one desktop:
Two cases:
1. 1 desktop and 1 laptop:
Favorable cases = 
2. Both desktop:
Favorable cases = 
Total number of favorable cases = 8 + 6 = 14
Required probability is
.
d. 1 desktop and 1 laptop:
Favorable cases = 
Total number of cases = 15
Required probability is
.