Lamp posts were located at an equal distance of 15 m apart from one another, starting from the beginning of the road. Between every 2 lamp posts, there were 2 trees, planted 5 m apart.
- What was the distance between the first tree and the fourth tree?
- What was the distance between the fourth tree and the fourteenth tree?
- Given that the stretch of road was 135 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
= 15 ÷ 3
= 5
Distance between first and fourth tree
= 4 intervals
= 4 x 5
= 20 m
(b)
Distance between fourth and fourteenth tree
= 15 intervals
= 15 x 5
= 75 m
(c)
Distance between 2 lamp posts = 15 m
Number of sets of 15 m
= 135 ÷ 15
= 9
Number of trees
= 9 x 2
= 18
Answer(s): (a) 20 m; (b) 75 m; (c) 18