Answer:
0.625 = 62.5% probability that part B works for one year, given that part A works for one year.
Step-by-step explanation:
We use the conditional probability formula to solve this question. It is

In which
P(B|A) is the probability of event B happening, given that A happened.
is the probability of both A and B happening.
P(A) is the probability of A happening.
The probability that part A works for one year is 0.8 and the probability that part B works for one year is 0.6.
This means that 
The probability that at least one part works for one year is 0.9.
This means that: 
We also have that:

So


Calculate the probability that part B works for one year, given that part A works for one year.

0.625 = 62.5% probability that part B works for one year, given that part A works for one year.
You can make 22 batches of chocolate chip cookies. And for the second one you can make about 7 batches of lemon cookies
If the question is 2/3 cups of oil .
then the answer will be 5 1/3 cups
so ti think your answer will be A
Add 1 to both sides:

In cases like this, we have to remember that a root is always positive, so we can square both sides only assuming that

Under this assumption, we square both sides and we have

The solutions to this equation are

But since we can only accept solutions greater than -1, we discard
and accept
.
In fact, we have

and

which is the only solution.