medal and follow

Question

medal and follow

anonymous · Answer

After using a new rectangular cloth napkin, Mister Weston puts it in his washing machine, then in the dryer. When it comes out, its length and width are three-fourths their original sizes. How has the area of the napkin changed? 

Two napkins are shown. The first one is the original napkin. The second one is the napkin that has shrunk, which appears to be three-fourths the size of the original napkin. 

 It has been reduced to three-fourths its original area.

 It has been reduced to three-eighths its original area.

 It has been reduced to nine-sixteenths its original area.

 It has been reduced to twenty-seven sixty-fourths its original area.

solomonzelman · Answer

$\Large\color{black}{ \rm  l\times w=A}$

$\Large\color{blue}{ \rm    (\frac{3}{4}) l\times (\frac{3}{4})w=}$

$\Large\color{blue}{ \rm    (\frac{3}{4})^2~~ l\times w=}$

$\Large\color{blue}{ \rm    (\frac{9}{16})~ l\times w.}$

solomonzelman · Answer

Thus  the  new  napkin  is  9/16th  of  the  original  one.