A piece of ribbon 3900 cm long is cut into 3 parts, C, A and B.
C is 2 times as long as A.
B is 120 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 + 120
Length of C = 2 x (1 u + 120) = 2 u + 240
Total length of C, A and B
= 2 u + 240 + 1 u + 120 + 1 u
= 2 u + 1 u + 1 u + 240 + 120
= 4 u + 360
4 u + 360 = 3900
4 u = 3900 - 360
4 u = 3540
1 u = 3540 ÷ 4 = 885
Length of B shorter than C
= 2 u + 240 - 1 u
= 2 u - 1 u + 240
= 1 u + 240
= 1 x 885 + 240
= 885 + 240
= 1125 cm
(b)
Total length of C and A = 2 u + 240 + 1 u + 120
= 2 u + 1 u + 240 + 120
= 3 x 885 + 360 = 2655 + 360 = 3015 cm Answer(s): (a) 1125 cm; (b) 3015 cm