A rectangular carpet and a square carpet have equal areas. The square carpet has a side length of 4 m. The length of the rectangular carpet is 2 m less than three times its width. What are the dimensions of the rectangular carpet?

1 Answer
Nov 27, 2015

The dimensions are: #w=8/3m# #l=6m#

Explanation:

If we write the dimensions of rectangular carpet: width - #w#,
height - #h# then we can write, that:

#l=3w-2#

and

#w*(3w-2)=16#

The first equation comes from the sentence: "The length of the rectangular carpet is 2 m less than three times its width." The second comes from the fact that the area of the rectangular and square carpet is equal.

If we expand the equation we get:

#3w^2-2w-16=0#

#Delta=4-4*3*(-16)=4+192=196#

#sqrt(Delta)=14#

#w_1=(2-14)/6<0# We cannot take #w_1# because the dimensions of figures cannot be negative.

#w_2=(2+14)/6=16/6=8/3= 2 2/3#

Now if we know, that #w=8/3# we can calculate

#l=3w-2=8-2=6#

Answer:
The dimensions are: width - #8/3m#, height #6m#