A piece of ribbon 2400 cm long is cut into 3 parts, B, C and A.
B is 2 times as long as C.
A is 120 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 + 120
Length of B = 2 x (1 u + 120) = 2 u + 240
Total length of B, C and A
= 2 u + 240 + 1 u + 120 + 1 u
= 2 u + 1 u + 1 u + 240 + 120
= 4 u + 360
4 u + 360 = 2400
4 u = 2400 - 360
4 u = 2040
1 u = 2040 ÷ 4 = 510
Length of A shorter than B
= 2 u + 240 - 1 u
= 2 u - 1 u + 240
= 1 u + 240
= 1 x 510 + 240
= 510 + 240
= 750 cm
(b)
Total length of B and C = 2 u + 240 + 1 u + 120
= 2 u + 1 u + 240 + 120
= 3 x 510 + 360 = 1530 + 360 = 1890 cm Answer(s): (a) 750 cm; (b) 1890 cm