A piece of ribbon 3900 cm long is cut into 3 parts, C, B and A.
C is 2 times as long as B.
A is 140 cm shorter than B.
Give the answers in cm.
- How much shorter is A than C?
- What is the total length of C and B?
(a)
Choose the shortest length to be 1 u.
Length of A = 1 u
Length of B = 1 u + 140
Length of C = 2 x (1 u + 140) = 2 u + 280
Total length of C, B and A
= 2 u + 280 + 1 u + 140 + 1 u
= 2 u + 1 u + 1 u + 280 + 140
= 4 u + 420
4 u + 420 = 3900
4 u = 3900 - 420
4 u = 3480
1 u = 3480 ÷ 4 = 870
Length of A shorter than C
= 2 u + 280 - 1 u
= 2 u - 1 u + 280
= 1 u + 280
= 1 x 870 + 280
= 870 + 280
= 1150 cm
(b)
Total length of C and B = 2 u + 280 + 1 u + 140
= 2 u + 1 u + 280 + 140
= 3 x 870 + 420 = 2610 + 420 = 3030 cm Answer(s): (a) 1150 cm; (b) 3030 cm