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Fiber X cereal is 55% fiber. Fiber Max cereal is 70% fiber. [#permalink]
29 Aug 2018, 16:18

Expert's post

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Question Stats:

44% (01:23) correct
55% (02:17) wrong based on 9 sessions

Fiber X cereal is 55% fiber. Fiber Max cereal is 70% fiber. Sheldon combines an amount of the two cereals in a single bowl of mixed cereal that is 65% fiber. If the bowl contains a total of 12 ounces of cereal, how much of the cereal, in ounces, is Fiber X?

Re: Fiber X cereal is 55% fiber. Fiber Max cereal is 70% fiber. [#permalink]
31 Aug 2018, 02:43

I am sorry, I need have my head wraped around such type of question. would highly appriciate is someone can share a link to a video link to these type of questions.

Re: Fiber X cereal is 55% fiber. Fiber Max cereal is 70% fiber. [#permalink]
15 Oct 2018, 09:56

Use the weighted average formula to get the ratio of Fiber X to Fiber Max: [0.55X+0.70m][/x+m] = 0.65 where x is the amount of Fiber X and m is the amount of Fiber Max. This is not that different from the regular average formula—on the top, there is the total amount of fiber (55% of Fiber X and 70% of Fiber Max), which is divided by the total amount of cereal (x + m) to get the average. Simplify by multiplying both sides by (x + m): 0.55x + 0.70m = 0.65(x + m) 0.55x + 0.70m = 0.65x + 0.65m To simplify, multiply both sides of the equation by 100 to eliminate all the decimals: 55x + 70m = 65x + 65m 55x + 5m = 65x 5m = 10x m/x= 1/2 Since m and x are in a 2 to 1 ratio, 2/3 of the total is m and 1/3 of the total is x. Since the total is 12 ounces, Fiber X accounts for (12) = 4 ounces of the mixed cereal.

Re: Fiber X cereal is 55% fiber. Fiber Max cereal is 70% fiber. [#permalink]
15 Oct 2018, 09:56

One shortcut to this procedure is to note that the weighted average (65%) is 10% away from Fiber X’s percent and 5% away from Fiber Max’s percent. Since 10 is twice as much as 5, the ratio of the two cereals is 2 to 1. However, it is a 2

greprepclubot

Re: Fiber X cereal is 55% fiber. Fiber Max cereal is 70% fiber.
[#permalink]
15 Oct 2018, 09:56