Question

I want to cut 10 identical rectangles, each 6cm x 10 cm, from rectangular plastic boards that are 15 cm x 20cm. Each of the 10 rectangles must be cut out as one piece – joins are not allowed. What is the smallest number of plastic boards that I can use?

Answer 1

Answer: 5 plastic boards

Explanation:

Given that:

10 identical rectangles with dimension (6cm by 10cm) is to be cut from plastic boards

Dimension of plastic boards = (15 cm by 20 cm)

Each rectangle to be cut should be in one piece :

Hence number of rectangles that can be cut from one plastic board :

Dimension of plastic board / dimension of triangle to be cut

= (15cm by 20cm) / (6cm by 10 cm) = 2.5 by 2

Sine we do not joining:

2 identical rectangles can be cut from one plastic board.

Hence the smallest number of plastic boards to be used is :

Total number of identical rectangles needed / number that can be cut from one plastic board

= 10 / 2

= 5 plastic boards