Question

The length of a rectangle is 5 cm less than 3 times its width. The perimeter is 62 cm.

What is the length?

Answer 1

length=22 [cm].

Explanation:

1) if the length is 'l' and the width is 'w', then it is possible

2) to write the given perimeter: 62=2(l+w), - this is the 1st equation of system;

3) to write the condition 'the length of a rectangle is 5 cm less than 3 times its width' as 3w-5=l, - this is the 2d equation of the system.

4) using two equations above it is possible to make up the next system:

`\left \{ {{2(w+l)=62} \atop {3w-5=l}} \right. \ = > \ \left \{ {{w+l=31} \atop {3w-l=5}} \right. \ = > \ \left \{ {{l=22} \atop {w=9}} \right.`

5) finally, the length=22 [cm].