SOLUTION: A jumbo chocolate bar with a rectangular shape measures 15centimeters in​ length, 9centimeters in​ width, and 2centimeters in thickness. Due to escalating costs of​ coc

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Question 1137246: A jumbo chocolate bar with a rectangular shape measures
15centimeters in​ length,
9centimeters in​ width, and
2centimeters in thickness. Due to escalating costs of​ cocoa, the management has decided to reduce the volume of the bar by 20​%. To accomplish this​ reduction, management decides that the new bar should have the same 2centimeter​ thickness, but the length and width of each should be reduced by an equal number of centimeters. What should be the dimensions of the new candy​ bar?
a)The new candy bar measures__centimeters in​ length,
__centimeters in​ width, and__centimeters in thickness.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = reduction in cm of length and width
+%28+15+-+x+%29%2A%28+9+-+x+%29%2A2+=+.8%2A15%2A9%2A2+
+135+-+24x+%2B+x%5E2++=+108+
+x%5E2+-+24x++=+108+-+135+
+x%5E2+-+24x+%2B+27+=+0+
+x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
+x+=+%28+-%28-24%29+%2B-+sqrt%28+%28-24%29%5E2+-+4%2A1%2A27+%29%29%2F%282%2A1%29+
++x+=+%28+24+%2B-+sqrt%28+576+-+108+%29%29%2F2+
+x+=+%28+24+%2B+sqrt%28+468+%29%29%2F2+
+x+=+%28+24+%2B+21.6333+%29%2F2+ ( too large )
+x+=+%28+24+-+21.6333+%29%2F2+
+x+=+2.3667%2F2+
+x+=+1.18335+
---------------------
Length = 13.8167
Width = 7.81665
thickness = 2
---------------------
check:
+13.8167%2A7.81665%2A2+=+216+
+.8%2A15%2A9%2A2+=+216+
OK