A piece of ribbon 1100 cm long is cut into 3 parts, C, A and B.
C is 3 times as long as A.
B is 140 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 + 140
Length of C = 3 x (1 u + 140) = 3 u + 420
Total length of C, A and B
= 3 u + 420 + 1 u + 140 + 1 u
= 3 u + 1 u + 1 u + 420 + 140
= 5 u + 560
5 u + 560 = 1100
5 u = 1100 - 560
5 u = 540
1 u = 540 ÷ 5 = 108
Length of B shorter than C
= 3 u + 420 - 1 u
= 3 u - 1 u + 420
= 2 u + 420
= 2 x 108 + 420
= 216 + 420
= 636 cm
(b)
Total length of C and A = 3 u + 420 + 1 u + 140
= 3 u + 1 u + 420 + 140
= 4 x 108 + 560 = 432 + 560 = 992 cm Answer(s): (a) 636 cm; (b) 992 cm