T = 2 π / | 4/7 |
T = 2 π / 4/7
T = 2 π × 7 / 4
T = 7 π / 2
Thus the correct answer is option A .
Answer:
8a
Step-by-step explanation:
group all similar terms
3a + 5a = 8a
Step-by-step explanation:
the probability of A working is 60% or 0.6, so the probability it does not work is 40% or 0.4.
the probability of B working is 90% or 0.9, so the probability it does not work is 10% or 0.1.
plan 1
it is the probabilty that either A works, or (if it is not working) B works.
0.6 + 0.4×0.9 = 0.6 + 0.36 = 0.96
plan 2
either B works, or (if it is not working) A works
0.9 + 0.1×0.6 = 0.9 + 0.06 = 0.96
both plans have the same success probability.