A piece of ribbon 1200 cm long is cut into 3 parts, B, A and C.
B is 4 times as long as A.
C is 180 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 + 180
Length of B = 4 x (1 u + 180) = 4 u + 720
Total length of B, A and C
= 4 u + 720 + 1 u + 180 + 1 u
= 4 u + 1 u + 1 u + 720 + 180
= 6 u + 900
6 u + 900 = 1200
6 u = 1200 - 900
6 u = 300
1 u = 300 ÷ 6 = 50
Length of B longer than A
= 4 u + 720 - (1 u + 180)
= 4 u - 1 u + 720 - 180
= 3 u + 540
= 3 x 50 + 540
= 150 + 540
= 690 cm
(b)
Total length of B and C
= 4 u + 720 + 1 u
= 5 u + 720
= 5 x 50 + 720
= 250 + 720
= 970 cm
Answer(s): (a) 690 cm; (b) 970 cm