Answer:
Bill: 8 years
Hoang: 13 years
Step-by-step explanation:
Let's say Hoang has been a nurse for H years and Bill has been a nurse for B years.
Hoang has been a nurse for 5 years longer than Bill. This means that B + 5 = H
Next, 3 years ago, she had been there twice as long.
(B-3) and (H-3) represent Bill and Hoang 3 years ago respectively.
(B-3) * 2 = (H-3)
We thus have two equations
B+5 = H
(B-3) * 2 = H-3
Substitute B+5 for H in the second equation
2*B - 6 = B+5-3
2B-6 = B+2
add 6 to both sides to put all the constants on one side
2B = B + 8
subtract B from both sides to isolate the variable
B = 8
H = B+5 = 13
