A piece of ribbon 2500 cm long is cut into 3 parts, B, C and A.
B is 2 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 = 2 x (1 u + 140) = 2 u + 280
Total length of B, C and A
= 2 u + 280 + 1 u + 140 + 1 u
= 2 u + 1 u + 1 u + 280 + 140
= 4 u + 420
4 u + 420 = 2500
4 u = 2500 - 420
4 u = 2080
1 u = 2080 ÷ 4 = 520
Length of A shorter than B
= 2 u + 280 - 1 u
= 2 u - 1 u + 280
= 1 u + 280
= 1 x 520 + 280
= 520 + 280
= 800 cm
(b)
Total length of B and C = 2 u + 280 + 1 u + 140
= 2 u + 1 u + 280 + 140
= 3 x 520 + 420 = 1560 + 420 = 1980 cm Answer(s): (a) 800 cm; (b) 1980 cm