A piece of ribbon 3500 cm long is cut into 3 parts, B, A and C.
B is 2 times as long as A.
C is 280 cm shorter than A.
Give the answers in cm.
- How much longer is B than A?
- What is the total length of B and C?
(a)
Choose the shortest length to be 1 u.
Length of C = 1 u
Length of A = 1 u + 280
Length of B = 2 x (1 u + 280) = 2 u + 560
Total length of B, A and C
= 2 u + 560 + 1 u + 280 + 1 u
= 2 u + 1 u + 1 u + 560 + 280
= 4 u + 840
4 u + 840 = 3500
4 u = 3500 - 840
4 u = 2660
1 u = 2660 ÷ 4 = 665
Length of B longer than A
= 2 u + 560 - (1 u + 280)
= 2 u - 1 u + 560 - 280
= 1 u + 280
= 1 x 665 + 280
= 665 + 280
= 945 cm
(b)
Total length of B and C
= 2 u + 560 + 1 u
= 3 u + 560
= 3 x 665 + 560
= 1995 + 560
= 2555 cm
Answer(s): (a) 945 cm; (b) 2555 cm