A piece of ribbon 3200 cm long is cut into 3 parts, B, A and C.
B is 5 times as long as A.
C is 160 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 + 160
Length of B = 5 x (1 u + 160) = 5 u + 800
Total length of B, A and C
= 5 u + 800 + 1 u + 160 + 1 u
= 5 u + 1 u + 1 u + 800 + 160
= 7 u + 960
7 u + 960 = 3200
7 u = 3200 - 960
7 u = 2240
1 u = 2240 ÷ 7 = 320
Length of B longer than A
= 5 u + 800 - (1 u + 160)
= 5 u - 1 u + 800 - 160
= 4 u + 640
= 4 x 320 + 640
= 1280 + 640
= 1920 cm
(b)
Total length of B and C
= 5 u + 800 + 1 u
= 6 u + 800
= 6 x 320 + 800
= 1920 + 800
= 2720 cm
Answer(s): (a) 1920 cm; (b) 2720 cm