A piece of ribbon 1400 cm long is cut into 3 parts, B, A and C.
B is 3 times as long as A.
C is 120 cm shorter than A.
Give the answers in cm.
- How much shorter is C than B?
- What is the total length of B and A?
(a)
Choose the shortest length to be 1 u.
Length of C = 1 u
Length of A = 1 u + 120
Length of B = 3 x (1 u + 120) = 3 u + 360
Total length of B, A and C
= 3 u + 360 + 1 u + 120 + 1 u
= 3 u + 1 u + 1 u + 360 + 120
= 5 u + 480
5 u + 480 = 1400
5 u = 1400 - 480
5 u = 920
1 u = 920 ÷ 5 = 184
Length of C shorter than B
= 3 u + 360 - 1 u
= 3 u - 1 u + 360
= 2 u + 360
= 2 x 184 + 360
= 368 + 360
= 728 cm
(b)
Total length of B and A = 3 u + 360 + 1 u + 120
= 3 u + 1 u + 360 + 120
= 4 x 184 + 480 = 736 + 480 = 1216 cm Answer(s): (a) 728 cm; (b) 1216 cm