Need help on this thank you

A. n = 1/63

B. k = 13/3

C. g = 5

D. w = 21/17

Step-by-step explanation:

A. 9n = 15/7 - 2

9n = 15-14/7

9n = 1/7

n = 1/7 ÷ 9

= 1/7 × 1/9

n = 1/63

B. 1/3 = k - 4

1/3 + 4 = k

1+12/3 = k

13 /3 = k

k = 13/3

C. g - 2/5g = 3

5g-2g/5 = 3

3/5g = 3

g = 3 ÷ 3/5

= 3 × 5/3

= 15/3

g = 5

D. 3/7w + 2w = 3

3w+14w/7 = 3

17/7w = 3

w = 3 ÷ 17/7

= 3 × 7/17

= 21/17

w = 21/17

The tree diagram of the problem above is attached
There are four outcomes of the two events,

First test - Cancer, Second Test - Cancer, the probability is 0.0396
First test - Cancer, Second Test - No Cancer, the probability is 0.0004
First test -  No Cancer, Second Test - There is cancer, the probability is 0.0096
First test - No cancer, Second Test - No cancer, the probability is 0.9054

The probability of someone picked at random has cancer given that test result indicates cancer is  

The probability of someone picked at random has cancer given that test result indicates no cancer is