Question

The perimeter of a floor is 40m. The length is

three times as long as the widtb.
(a) What is the length of this floor?
(b) What is its area ?​

Answer 1

• length: 15 m
• area: 75 m²

Explanation:

(a) Let L represent the length of the floor. The length is 3 times the width, so we have L = 3W, or W = L/3.

P = 2(L+W) . . . . the formula for the perimeter of a rectangle

Filling in the known values, we have ...

40 = 2(L +L/3)

20 = (4/3)L . . . . divide by 2 and collect terms

15 = L . . . . . . . . multiply by 3/4

The length of the floor is 15 m.

__

(b) From above, the width is ...

W = L/3 = (15 m)/3 = 5 m.

The area is given by the formula ...

A = LW = (15 m)(5 m)

A = 75 m²

The area of the floor is 75 square meters.