Final answer:
The cost of electricity necessary to produce 10 tons of aluminum is $77.50.
Step-by-step explanation:
To determine the cost of electricity necessary to produce 10 tons of aluminum, we need to know the proportion of electricity used for aluminum production compared to magnesium production. According to the information provided, the electrolysis of aluminum uses 5% of all the electricity in the country. Therefore, the cost of electricity to produce 10 tons of aluminum can be calculated as follows:
Total electricity cost = Cost of electricity per ton of metal x Number of tons of aluminum x Proportion of electricity used for aluminum
Total electricity cost = $155/ton x 10 tons x 0.05
Total electricity cost = $77.50