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A chocolate bar without the wrapping weighs 160g. This is the net weight

a. Mini chocolate bars are being sold of which all the proportions are half of the normal chocolate bar. They are made of the same chocolate. What is the net weight of these bars?

b. A normal chocolate bar is 20cm by 4cm by 1,5cm. They are wrapped in tinfoil. Explain that for an normal chocolate bar you need 232cm^2

c. How many cm^2 of tinfoil would you need at minimum for the the mini chocolate bar?

 Apr 21, 2019
 #1
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normal choc bar    x *y =xy  = 160 gm

                          1/2 x * 1/2 y = 1/4 xy =      1/4  160 = 40 gm

 

 

surface area of normal chocolate bar =   2  *  20 *4   = 160

           plus  2  *   20 *1.5     = 60

           plus   2 *    4 * 1.5     = 12          160+60+12 = 232 cm^2   to cover the bar

 

mini bar is  10 x 2 x .75

   2*     10 x 2 = 40

   2 *    10 x .75 = 15

   2 *     2*.75 = 3             40 + 15 + 3 = 58 cm^2

 Apr 22, 2019

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