Question

A designer increased the area of a tapestry by 20%. By what percent the width of tapestry was decreased in the process, if its length was increased by 50%?

Answer 1

20%

Explanation:

Let w and l represent the original width and length. Let W and L represent the width and length of the larger tapestry. The corresponding areas are the product of length and width.

LW = 1.2·lw . . . . . the new area is 20% larger than the original

(1.5·l)W = 1.2·lw . . . the new length is 50% larger than the original

W = (1.2·lw)/(1.5·l) = 0.8·w . . . . . divide by the coefficient of W

The new width is 80% of the old width, hence the width was decreased by 20%.