A piece of ribbon 4000 cm long is cut into 3 parts, C, A and B.
C is 2 times as long as A.
B is 240 cm shorter than A.
Give the answers in cm.
- How much longer is C than A?
- What is the total length of C and B?
(a)
Choose the shortest length to be 1 u.
Length of B = 1 u
Length of A = 1 u + 240
Length of C = 2 x (1 u + 240) = 2 u + 480
Total length of C, A and B
= 2 u + 480 + 1 u + 240 + 1 u
= 2 u + 1 u + 1 u + 480 + 240
= 4 u + 720
4 u + 720 = 4000
4 u = 4000 - 720
4 u = 3280
1 u = 3280 ÷ 4 = 820
Length of C longer than A
= 2 u + 480 - (1 u + 240)
= 2 u - 1 u + 480 - 240
= 1 u + 240
= 1 x 820 + 240
= 820 + 240
= 1060 cm
(b)
Total length of C and B
= 2 u + 480 + 1 u
= 3 u + 480
= 3 x 820 + 480
= 2460 + 480
= 2940 cm
Answer(s): (a) 1060 cm; (b) 2940 cm