Cocoa shortage :(

Question

A jumbo chocolate bar with a rectangular shape measures 13cm in length, 8cm in width, and 2cm in thickness. Volume of candy bar needs to be reduced by 10%. The thickness can stay the same but the length and width should be reduced by an equal amount of cm. What should the new dimensions be?

Answer 1

The new volume must be 187.2 cm³  (0.9)(13)(8)(2)

(13 - x)(8 - x)(2) = 187.2

 

Can you solve for x and answer?