A piece of ribbon 3900 cm long is cut into 3 parts, B, A and C.
B is 3 times as long as A.
C is 240 cm shorter than A.
Give the answers in cm.
- How much longer is B than A?
- What is the total length of B and C?
(a)
Choose the shortest length to be 1 u.
Length of C = 1 u
Length of A = 1 u + 240
Length of B = 3 x (1 u + 240) = 3 u + 720
Total length of B, A and C
= 3 u + 720 + 1 u + 240 + 1 u
= 3 u + 1 u + 1 u + 720 + 240
= 5 u + 960
5 u + 960 = 3900
5 u = 3900 - 960
5 u = 2940
1 u = 2940 ÷ 5 = 588
Length of B longer than A
= 3 u + 720 - (1 u + 240)
= 3 u - 1 u + 720 - 240
= 2 u + 480
= 2 x 588 + 480
= 1176 + 480
= 1656 cm
(b)
Total length of B and C
= 3 u + 720 + 1 u
= 4 u + 720
= 4 x 588 + 720
= 2352 + 720
= 3072 cm
Answer(s): (a) 1656 cm; (b) 3072 cm