A piece of ribbon 3300 cm long is cut into 3 parts, A, B and C.
A is 2 times as long as B.
C is 140 cm shorter than B.
Give the answers in cm.
- How much shorter is C than A?
- What is the total length of A and B?
(a)
Choose the shortest length to be 1 u.
Length of C = 1 u
Length of B = 1 u + 140
Length of A = 2 x (1 u + 140) = 2 u + 280
Total length of A, B and C
= 2 u + 280 + 1 u + 140 + 1 u
= 2 u + 1 u + 1 u + 280 + 140
= 4 u + 420
4 u + 420 = 3300
4 u = 3300 - 420
4 u = 2880
1 u = 2880 ÷ 4 = 720
Length of C shorter than A
= 2 u + 280 - 1 u
= 2 u - 1 u + 280
= 1 u + 280
= 1 x 720 + 280
= 720 + 280
= 1000 cm
(b)
Total length of A and B = 2 u + 280 + 1 u + 140
= 2 u + 1 u + 280 + 140
= 3 x 720 + 420 = 2160 + 420 = 2580 cm Answer(s): (a) 1000 cm; (b) 2580 cm