Answer:
Whats the answer choices?
Step-by-step explanation:
Answer:
a) Mean Time to failure (MTTF) = (10^7) hours
b) Availability of the system = 1
c) Mean Time to failure for 1000 processors = 10^4 hours.
Step-by-step explanation:
a) Failures in time (FIT) is traditionally reported as failure Per billion hours Of Operation.
1 billion = (10^9)
FIT = 100/(10^9) = 10^-7
MTTF = 1/FIT = 1/(10^-7) = (10^7) hours
b) Availability of the system = MTTF/(MTTF + MTTR)
MTTR = mean time to repair = 24hours
Availability of the system = (10^7)/((10^7) + 24) = 0.9999 = 1
c) FIT = 1000 (processors) × 100 (FIT per processor) = (10^5) per billion hours of operations = (10^5)/(10^9) = 10^-4
MTTF = 1/FIT = 1/(10^-4) = (10^4) hours
QED!!
Each digit can be 0-9 ( 10 numbers)
there are 9 numbers in a social security number
multiply 10 nine times:
10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 = 1,000,000,000 ( 1 billion) possibilities.
the restriction is it can't be all zeros so subtract 1 from the total
1,000,000,000 - 1 = 999,999,999 combinations
