Answer: 
Step-by-step explanation:
Given
Marcos purchased a sailboat for 
Each year the boat will decrease in value by 
After 1 year it is

after another year it becomes

After
years it is


Whats the rest of the problem?
The share of Natasha is £ 42
<em><u>Solution:</u></em>
£70 is divided between Natasha, Richard & Stephen
Total amount = 70
Let the share of natasha be "x"
Let the share of richard be "y"
Let the share of stephen be "z"
Natasha gets twice as much as Richard
x = 2y ------ eqn 1
Richard gets three times as much as Stephen
y = 3z
----- eqn 2
Total amount = 70
share of natasha + share of richard + share of stephen = 70
x + y + z = 70
Substitute eqn 1 and eqn 2

Substitute y = 21 in eqn 1
x = 2y = 2(21) = 42
x = 42
Thus natasha gets £ 42
Since he has an annual salary, the salary stays the same, making it the y intercept.
As for 250, it goes to every car he sells, making it the slope
S = y + mc (y = y intercept, m = slope)
Plug in the values to see
Solution: A. 45,000 + 250C