Question

21. A rectangular napkin costs $3.25. A similar tablecloth is five times longer and five times wider. How muchwould you expect to pay for the tablecloth?A. $48.75B. $16.25C. $32.50D. $81.25

Answer 1

Notice that the area of the tablecloth will be 25 times bigger than the area of the napkin. If L and W are the dimensions of the napkin, then its area is given by:

$A_N=L\cdot W$

Compute the area of the table cloth if its length is 5L and its width is 5W:

$A_T=5L\cdot5W=25L\cdot W=25\cdot A_N$

Assuming that the cost is directly proportional to the area, then the cost of the tablecloth will be 25 times the cost of the napkin:

$25\times3.25=81.25$

Therefore, we can expect to pay $81.25 for the tablecloth.