A piece of ribbon 1800 cm long is cut into 3 parts, A, B and C.
A is 3 times as long as B.
C is 240 cm shorter than B.
Give the answers in cm.
- How much shorter is C than A?
- What is the total length of A and B?
(a)
Choose the shortest length to be 1 u.
Length of C = 1 u
Length of B = 1 u + 240
Length of A = 3 x (1 u + 240) = 3 u + 720
Total length of A, B and C
= 3 u + 720 + 1 u + 240 + 1 u
= 3 u + 1 u + 1 u + 720 + 240
= 5 u + 960
5 u + 960 = 1800
5 u = 1800 - 960
5 u = 840
1 u = 840 ÷ 5 = 168
Length of C shorter than A
= 3 u + 720 - 1 u
= 3 u - 1 u + 720
= 2 u + 720
= 2 x 168 + 720
= 336 + 720
= 1056 cm
(b)
Total length of A and B = 3 u + 720 + 1 u + 240
= 3 u + 1 u + 720 + 240
= 4 x 168 + 960 = 672 + 960 = 1632 cm Answer(s): (a) 1056 cm; (b) 1632 cm