(a) Assume the length of the wooden block  is L and the width is W

Volume of block before reduction = 14LW

Length of block after reduction = (3/5) L

Breadth of block after reduction = (3/4)W

Volume of block after reduction = (3/5)L x (3/4) W x 14  = [ (9 x 14) /20 ] LW

Hence fraction final volume of the  block against the original volume 

=      [ ( 9 x 14) /20 ] LW

         ——————–   

                  14 LW

= 9/20

(b)    9u -> 819  => u = 91   Hence 20u = 1820

Let BA = base area of the original block

BA x height = 1820

BA x 14 = 1820

BA = 1820 / 14  = 130

Hence base area of the original block = 130cm²

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thanks

a.

Original volume of block = 14LW

Area of block after reduction = (3/5) L * (3/4) W = (9/20)LW

Volume of block after reduction = (9/20)LW * 14 =(63/10)LW = 6.3LW

So fraction of original volume = 6.3/14 = 0.45 #

b. 6.3LW = 819 cm3
LW = 130 cm2 #