A piece of ribbon 3600 cm long is cut into 3 parts, C, A and B.
C is 4 times as long as A.
B is 180 cm shorter than A.
Give the answers in cm.
- How much shorter is B than C?
- What is the total length of C and A?
(a)
Choose the shortest length to be 1 u.
Length of B = 1 u
Length of A = 1 u + 180
Length of C = 4 x (1 u + 180) = 4 u + 720
Total length of C, A and B
= 4 u + 720 + 1 u + 180 + 1 u
= 4 u + 1 u + 1 u + 720 + 180
= 6 u + 900
6 u + 900 = 3600
6 u = 3600 - 900
6 u = 2700
1 u = 2700 ÷ 6 = 450
Length of B shorter than C
= 4 u + 720 - 1 u
= 4 u - 1 u + 720
= 3 u + 720
= 3 x 450 + 720
= 1350 + 720
= 2070 cm
(b)
Total length of C and A = 4 u + 720 + 1 u + 180
= 4 u + 1 u + 720 + 180
= 5 x 450 + 900 = 2250 + 900 = 3150 cm Answer(s): (a) 2070 cm; (b) 3150 cm