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.
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
Ooops -- thanks, Steve for the correction!
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
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
(a) You have correctly stated the lengths of the pieces in terms of x.
- The length of the first piece: 21 cm - x cm
- The length of the second piece: (21 cm - x cm) - 3 cm
- The length of the third piece: (21 cm - x cm) * 2 cm
(b) To represent the sum of the lengths of the three pieces in terms of x, you need to add the lengths of each piece together.
Sum = (21 cm - x cm) + ((21 cm - x cm) - 3 cm) + ((21 cm - x cm) * 2 cm)
Simplifying the expression:
Sum = 21 cm - x cm + 21 cm - x cm - 3 cm + 42 cm - 2x cm
Combining like terms:
Sum = 63 cm - 4x cm
Therefore, the expression in terms of x that represents the sum of the lengths of the three pieces is 63 cm - 4x cm.