Mark A machine has two parts labeled A and B. 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. The probability that at least one part works for one year is 0.9. 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.

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.

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".

2

step-by-step explanation: