A piece of ribbon 4200 cm long is cut into 3 parts, C, A and B.
C is 3 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 = 3 x (1 u + 120) = 3 u + 360
Total length of C, A and B
= 3 u + 360 + 1 u + 120 + 1 u
= 3 u + 1 u + 1 u + 360 + 120
= 5 u + 480
5 u + 480 = 4200
5 u = 4200 - 480
5 u = 3720
1 u = 3720 ÷ 5 = 744
Length of B shorter than C
= 3 u + 360 - 1 u
= 3 u - 1 u + 360
= 2 u + 360
= 2 x 744 + 360
= 1488 + 360
= 1848 cm
(b)
Total length of C and A = 3 u + 360 + 1 u + 120
= 3 u + 1 u + 360 + 120
= 4 x 744 + 480 = 2976 + 480 = 3456 cm Answer(s): (a) 1848 cm; (b) 3456 cm