1. **Problem Statement:** We need to analyze and compare the cost functions for two cellphone packages: Economy and Gold. 2. **Formulas:** - Economy package cost: $$C_E = 20 + 1 \times n$$ where $n$ is the number of minutes. - Gold package cost: $$C_G = 40 + 0.5 \times n$$ where $n$ is the number of minutes. 3. **Calculate missing values:** - For Economy package, at $n=40$ minutes: $$C_E = 20 + 1 \times 40 = 60$$ - For Gold package, at $n=100$ minutes: $$C_G = 40 + 0.5 \times 100 = 40 + 50 = 90$$ (matches given) 4. **Find missing values A and B:** - Economy package at $n=A$ minutes equals cost $A$ rands, so $C_E = A$: $$20 + 1 \times A = A \implies 20 + A = A \implies 20 = 0$$ which is impossible, so likely a typo or $A$ is the cost at $n=40$ which is 60. - Gold package at $n=B$ minutes with cost 165 rands: $$165 = 40 + 0.5 \times B \implies 0.5B = 125 \implies B = 250$$ 5. **Summary:** - Economy package cost function: $$C_E = 20 + n$$ - Gold package cost function: $$C_G = 40 + 0.5n$$ - Missing Economy cost at 40 minutes is 60 rands. - Missing Gold package time for 165 rands is 250 minutes. 6. **Interpretation:** - Economy package is cheaper for low usage but costs more as minutes increase. - Gold package has a higher base cost but cheaper per minute. Final answers: - Economy package cost at 40 minutes: 60 rands. - Gold package time for 165 rands: 250 minutes.