Answer:
x=17, y=9. (17, 9).
Step-by-step explanation:
x+y=26
3x+8y=123
------------------
x=26-y
3(26-y)+8y=123
78-3y+8y=123
78+5y=123
5y=123-78
5y=45
y=45/5
y=9
x=26-9=17
Answer:
I got -2.7
Step-by-step explanation:
Answer:
39.17% probability that a woman in her 60s who has a positive test actually has breast cancer
Step-by-step explanation:
Bayes Theorem:
Two events, A and B.

In which P(B|A) is the probability of B happening when A has happened and P(A|B) is the probability of A happening when B has happened.
In this question:
Event A: Positive test.
Event B: Having breast cancer.
3.65% of women in their 60s get breast cancer
This means that 
A mammogram can typically identify correctly 85% of cancer cases
This means that 
Probability of a positive test.
85% of 3.65% and 100-95 = 5% of 100-3.65 = 96.35%. So

What is the probability that a woman in her 60s who has a positive test actually has breast cancer?

39.17% probability that a woman in her 60s who has a positive test actually has breast cancer