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Pre Algebra Question Help?

A freight train with 80 cars transports coal and iron ore. Each car carries either 100 tons of coal or 90 tons of iron ore. A. Let c represent the number of cars carrying coal. Write and simplify an expression in terms of c for the total weight of the freight transported by the train. B. Suppose 28 of the train's cars carry coal. What is the total weight of all the freight?

Public Comments

1. A. If c is the number of cars carrying coal, then 80 - c is the number of cars carrying iron ore because there are 80 cars total. Therefore, the total weight is 100c + 90(80 - c) tons. B. 100(28) + 90(80 - 28) = 7480 tons
2. T = total weight c = coal cars 80-c = iron cars A) 100c + 90(80-c) = T B) c = 28 so 90 - c = 90 - 28 = 62 28 coal, 62 iron 100*28 + 90*62 = T You do the math.