A piece of ribbon 3600 cm long is cut into 3 parts, C, A and B.
C is 2 times as long as A.
B is 280 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 + 280
Length of C = 2 x (1 u + 280) = 2 u + 560
Total length of C, A and B
= 2 u + 560 + 1 u + 280 + 1 u
= 2 u + 1 u + 1 u + 560 + 280
= 4 u + 840
4 u + 840 = 3600
4 u = 3600 - 840
4 u = 2760
1 u = 2760 ÷ 4 = 690
Length of C longer than A
= 2 u + 560 - (1 u + 280)
= 2 u - 1 u + 560 - 280
= 1 u + 280
= 1 x 690 + 280
= 690 + 280
= 970 cm
(b)
Total length of C and B
= 2 u + 560 + 1 u
= 3 u + 560
= 3 x 690 + 560
= 2070 + 560
= 2630 cm
Answer(s): (a) 970 cm; (b) 2630 cm