A piece of ribbon 3900 cm long is cut into 3 parts, B, A and C.
B is 4 times as long as A.
C is 210 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 + 210
Length of B = 4 x (1 u + 210) = 4 u + 840
Total length of B, A and C
= 4 u + 840 + 1 u + 210 + 1 u
= 4 u + 1 u + 1 u + 840 + 210
= 6 u + 1050
6 u + 1050 = 3900
6 u = 3900 - 1050
6 u = 2850
1 u = 2850 ÷ 6 = 475
Length of B longer than A
= 4 u + 840 - (1 u + 210)
= 4 u - 1 u + 840 - 210
= 3 u + 630
= 3 x 475 + 630
= 1425 + 630
= 2055 cm
(b)
Total length of B and C
= 4 u + 840 + 1 u
= 5 u + 840
= 5 x 475 + 840
= 2375 + 840
= 3215 cm
Answer(s): (a) 2055 cm; (b) 3215 cm