Question

The length of a rectangle is 5 meters greater than the width. The perimeter is 150 meters, find the width and length

Answer 1

let the width be x metres

length be (x+5) metres

perimeter= 2(l+b)

so 150= 2(x+5+x)

150 =2(2x+5)

75 =2x+5

x= 35

so width= 35 metres

 length = 35+5 =40 metres

Answer 2

Let L = the length of the rectangle and W = its width.

 

We have two unknowns (L and W), so we need two equations:

 

L = W + 5            The length of the rectangle is 5 m greater than its width

150 = 2L + 2W     The perimeter is 150m

 

Substitute W+5 in place of L in the perimeter equation and solve for L:

150 = 2L + 2W                 [Perimeter equation]

150 = 2(W+5) + 2W         [Substituted W+5 in place of L]

150 = 2W + 10 + 2W

150 = 4W + 10

140 = 4W

 

35 = W

 

Solve for L

L = W + 5

L = 35 + 5

 

L = 40

 

Check:

150 = 2L + 2W

150 = 2*40 + 2*35

150 = 80 + 70

150 = 150

CHECK!