A piece of ribbon 3800 cm long is cut into 3 parts, B, C and A.
B is 3 times as long as C.
A is 140 cm shorter than C.
Give the answers in cm.
- How much shorter is A than B?
- What is the total length of B and C?
(a)
Choose the shortest length to be 1 u.
Length of A = 1 u
Length of C = 1 u + 140
Length of B = 3 x (1 u + 140) = 3 u + 420
Total length of B, C and A
= 3 u + 420 + 1 u + 140 + 1 u
= 3 u + 1 u + 1 u + 420 + 140
= 5 u + 560
5 u + 560 = 3800
5 u = 3800 - 560
5 u = 3240
1 u = 3240 ÷ 5 = 648
Length of A shorter than B
= 3 u + 420 - 1 u
= 3 u - 1 u + 420
= 2 u + 420
= 2 x 648 + 420
= 1296 + 420
= 1716 cm
(b)
Total length of B and C = 3 u + 420 + 1 u + 140
= 3 u + 1 u + 420 + 140
= 4 x 648 + 560 = 2592 + 560 = 3152 cm Answer(s): (a) 1716 cm; (b) 3152 cm