Location Transport

simplifying variable expression problem! urgent.?

a freight trian 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 coal 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 train's cars carry coal.what is the total weight of all the freight?

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2. a freight trian 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 coal carrying coal.write and simplify an expression in terms of c for the total weight of the freight transported by the train. 80 cars (C)oal plus (I)ron =80 weight = 100(C) + 90(I) C=80-I substitute for C weight=100(80-I)+90(I) weight=8000-100(I)+90(I) weight=8000-10(I) b.suppose 28 train's cars carry coal.what is the total weight of all the freight? C+I=80 C=28 I=52 100(28)+90(52) 2800+4680 7480 tons