Size - Squares

[Guest]

A box is to be constructed from a sheet of tin. The box is to be made by cutting squares from the corners and folding up the remaining edges. The completed box has a length 3 times the width. Determine size of square to be removed.

Dimensions of tin - 12 cm. by 16 cm.

Finished box - L = 3W

My partial attempt:

Area of sheet of tin - 12 x 16 = 192 sq. cm.

Let X = size of square removed.

(12 - 2X) + (16 - 2X)

How do I proceed ?

[Guest]

part your answer......
Let X = size of square removed.....the length of the side of the square corner

(12 - 2X) + (16 - 2X) .....why did you add them????
..................

(12 - 2X) is the width of the box
And (16 - 2X) is the length of the box

And the question tell you that the length is 3 times the width

So 3(12 - 2X) = (16 - 2X)

36 - 6X = 16 - 2X

20 = 4X ....so X = 5 cms

So square is 5 cm by 5 cm.

[Guest]

Thanks.

"(12 - 2X) + (16 - 2X) .....why did you add them????" My error - wasn't sure.

A question:
"(12 - 2X) + (16 - 2X)"

Could the FOIL method be used to solve also ?

[Guest]

Please reply.

[Guest]

A question:
"(12 - 2X) + (16 - 2X)"

Could the FOIL method be used to solve also ?

No FOIL could not be used. This is the addition of 2 algebraic terms
FOIL is for the product of 2 algebriac terms

For this question the terms need to be equated....one of the terms was equal to 3 times the other
That meant using an equation to equate them.

[Guest]

Thanks again.