# Mathematics

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A drinking straw of length 21 cm is cut into 3 pieces

the length of the first piece is x cm

the second piece is 3cm shorter than the 1st piece

the third piece is twice as long as first piece

(a) state in terms of x the length of the pieces (i think i figured that one out...1st piece= 21cm-xcm, 2nd piece= xcm-3cm and the 3rd piece= xcm X 2cm i don't know if its right)

(b) write an expression in terms of x to represent the sum of the lengths of 3 pieces.

• Mathematics -

You're on the right track.

I'd state it this way.

x + x - 3 + 3x = 21

5x = 24

x = 24/5 = 4.8 cm

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

4.8 + 1.8 + 14.4 = 21

• Mathematics -

Hmmm. I'd have said (since the 3rd piece is twice as long as the first):

x + x-3 + 2x = 21
4x = 24
x = 6

• Mathematics - Thanks, Steve -

Ooops -- thanks, Steve for the correction!

• Mathematics -

Hi there, you both, did not answer on the part (b)write an expression in terms of x to represent the sum of the lengths of 3 pieces.

x + (x - 3) + 2x