If all 25 questions are different,
When order of selection counts:
P(25,7)
=25!/(25-7)!
=15511210043330985984000000/6402373705728000
=2422728000
When order of selection does not count count:
C(25,7)
=25!/(7!*(25-7)!)
=15511210043330985984000000/(6402373705728000*5040)
=480700
Answer:
C. X= -2.01 and x= 1.67
Step-by-step explanation:

Answer:

Step-by-step explanation:
Solve for
:

-Subtract
on both sides:


So, therefore, the final answer is
.
Answer:
b
Step-by-step explanation:
First computer takes x min. For 1 min it does 1/x part of work.
Second computer takes (x+24) min. For one min it does 1/(x+24) part of work.
Both computers for one min do (1/x+1/(x+24)) part of work.
At the same time, both computers for one min do 1/9 part of work.