Duru has an ice-cream stand, which she opens on days that are forecasted to be warmer than 10°C.
When open for business, her daily profit, P, is a function of the number of cones she sells, n, and can be
modeled by the function P(n) = 2n - 20. Additionally, she finds that the number of cones she sells, C.
is a function of the average temperature, t, in degrees Celsius (°C), and can be modeled by the function
C(t) = 50 + 10(t – 10).
Find an explicit expression that gives Duru's profit on a day with an average temperature of t° C.