Question

PLSS HELP ME I NEED IT ASAPP TYSM ILY

Answer 1

Answers:

• He needs   310   grams of the 99% cocoa brand
• He needs    590    grams of the 70% cocoa brand

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Explanation:

Let's label the two brands of chocolate as A and B

• Brand A is 99% cocoa
• Brand B is 70% cocoa

Furthermore, define these variables

• x = amount of brand A
• y = amount of brand B

The amounts are in grams.

The two amounts must add to 900 grams, so x+y = 900. This can be solved to y = 900-x which we'll use later.

Since we have x grams of brand A, and brand A has 99% cocoa, this means 0.99x represents the amount of pure cocoa from brand A.

Similarly, brand B contributes another 0.70y grams of pure cocoa

Overall, we're dealing with 0.99x+0.70y grams of pure cocoa from the two brands mixed together.

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Rolf needs 900 grams of final product. He wants it to be 80% cocoa, which means 80% of the 900 is going to be pure cocoa

80% of 900 = 0.80*900 = 720

Rolf wants 720 grams of pure cocoa after mixing the two brands together.

So this leads to the second equation: 0.99x+0.70y = 720

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Let's apply substitution to replace y with 900-x

0.99x+0.70y = 720

0.99x+0.70( y ) = 720

0.99x + 0.70( 900-x ) = 720

At this point, we have a single variable in which we can isolate x fully.

0.99x + 0.70( 900-x ) = 720

0.99x + 0.70( 900) + 0.70(-x) = 720

0.99x + 630 - 0.70x = 720

0.29x = 720-630

0.29x = 90

x = 90/(0.29)

x = 310.344827586 which is approximate

Rounding to the nearest full gram, we get x = 310

Use this x value to find y

y = 900-x

y = 900-310.344827586

y = 589.655172414 which is also approximate

y = 590 when rounding to the nearest whole number

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In summary, we have

• x = 310
• y = 590

Meaning that Rolf will need 310 grams of brand A to mix with 590 grams of brand B.

If we plugged those values into x+y = 900, then that equation works out.

If we tried the second equation, then,

0.99x+0.70y = 720

0.99*310+0.70*590 = 720

719.9 = 720

The slight discrepancy is due to the fact we rounded those approximate x and y values to the nearest whole number. We would get better accuracy if we rounded to say the nearest tenth or hundredth.