A piece of ribbon 3200 cm long is cut into 3 parts, B, C and A.
B is 4 times as long as C.
A is 160 cm shorter than C.
Give the answers in cm.
- How much longer is B than C?
- What is the total length of B and A?
(a)
Choose the shortest length to be 1 u.
Length of A = 1 u
Length of C = 1 u + 160
Length of B = 4 x (1 u + 160) = 4 u + 640
Total length of B, C and A
= 4 u + 640 + 1 u + 160 + 1 u
= 4 u + 1 u + 1 u + 640 + 160
= 6 u + 800
6 u + 800 = 3200
6 u = 3200 - 800
6 u = 2400
1 u = 2400 ÷ 6 = 400
Length of B longer than C
= 4 u + 640 - (1 u + 160)
= 4 u - 1 u + 640 - 160
= 3 u + 480
= 3 x 400 + 480
= 1200 + 480
= 1680 cm
(b)
Total length of B and A
= 4 u + 640 + 1 u
= 5 u + 640
= 5 x 400 + 640
= 2000 + 640
= 2640 cm
Answer(s): (a) 1680 cm; (b) 2640 cm