Lamp posts were located at an equal distance of 18 m apart from one another, starting from the beginning of the road. Between every 2 lamp posts, there were 2 trees, planted 6 m apart.
- What was the distance between the first tree and the 6th tree?
- What was the distance between the sixth tree and the twelfth tree?
- Given that the stretch of road was 126 m, how many trees were there?
Lamp post ↔ tree ↔ tree ↔ Lamp post ↔ tree ↔ tree ↔ Lamp post ↔ tree ↔ tree ↔ Lamp post
(a)
Length of each gap
= 18 ÷ 3
= 6
Distance between first and 6th tree
= 7 intervals
= 7 x 6
= 42 m
(b)
Distance between sixth and twelfth tree
= 9 intervals
= 9 x 6
= 54 m
(c)
Distance between 2 lamp posts = 18 m
Number of sets of 18 m
= 126 ÷ 18
= 7
Number of trees
= 7 x 2
= 14
Answer(s): (a) 42 m; (b) 54 m; (c) 14