Question

The length of a rectangular piece of steel in a bridge in 5 meters less than a triple the width. The perimeter of the piece of steel is 30 meters. Find the length of the piece of steel. Find the width of the piece of steel.

Answer 1

Step 1

Write out the perimeters

Width W = m

Length L = 3m - 5

Perimeter = 30 meters

Step 2

Write formula for the perimeter of a rectangle.

Perimeter of a ractangle = 2L + 2W

Step 3

Substitute values.

30 = 2(3m - 5) + 2m

30 = 6m - 10 + 2m

30 + 10 = 8m

40 = 8m

m = 40/8

m = 5

Length = 3m - 5 = 3x5 - 5 = 15 - 5 = 10 meters

Width = 5 meters