Answer:
Here, The price of one box having N markers = Price of N markers + packaging charge
Let M be the price of one Marker and P' be the price of packaging of one box which is same for any size.
Since, The price of a box of 15 cloud markers is $12.70.
That is , 15 M + P' = 12.70 ---------(1)
Also, The price of a box of 42 cloud markers is $31.60,
That is, 42 M + P' = 31.60 ---------(2),
Equation (2) - Equation (1),
27 M = 18.90,
⇒ M = 0.7
By putting the value of P in equation (1),
We get,
10.5 + P' = 12.70 ⇒ P' = 2.2,
Thus, the price of one marker, M = 0.7
And, the price of packaging one box, P' = 2.2
Thus, the price of a box of 50 marker = 50 × M + P' = 50×0.7 + 2.2 = 35 + 2.2 = $ 37.2
And, the equation that shows the price(P) of a box of N markers,
P = 0.7 N + 2.2
