Lamp posts were located at an equal distance of 9 m apart from one another, starting from the beginning of the road. Between every 2 lamp posts, there were 2 trees, planted 3 m apart.
- What was the distance between the first tree and the 6th tree?
- What was the distance between the eighth tree and the fourteenth tree?
- Given that the stretch of road was 75 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
= 9 ÷ 3
= 3
Distance between first and 6th tree
= 7 intervals
= 7 x 3
= 21 m
(b)
Distance between eighth and fourteenth tree
= 9 intervals
= 9 x 3
= 27 m
(c)
Distance between 2 lamp posts = 9 m
Number of sets of 9 m
= 75 ÷ 9
= 8 r 3
Number of trees at a distance of 3 m
= 3 ÷ 3
= 1
Number of trees
= 8 x 2 + 1
= 17
Answer(s): (a) 21 m; (b) 27 m; (c) 17