Ben had 3.9 m of string. He used some of it to make the figure as shown.
- How much of the string did Andy use to make the figure? Leave your answer in the simplest form in terms of b.
- If b = 28, how much of the string was not used to make the figure? Leave your answer in m.
(a)
Total string used
= b + b + b + (3b - 10) + (b + 17)
= b + b + b + 3b + b - 10 + 17
= (7 b + 7) cm
(b)
1 m = 100 cm
3.9 m = 390 cm
Total string used if b = 28
= 7 b + 7
= 7(28) + 7
= 196 + 7
= 203 cm
Total string not used
= 390 - 203
= 187 cm
1 cm = 0.01 m
187 cm = 1.87 m
Answer(s): (a) (7b + 7) cm; (b) 1.87 m