Lamp posts were located at an equal distance of 21 m apart from one another, starting from the beginning of the road. Between every 2 lamp posts, there were 2 bushes, planted 7 m apart.
- What was the distance between the first bush and the 6th bush?
- What was the distance between the eighth bush and the tenth bush?
- Given that the stretch of road was 175 m, how many bushes were there?
Lamp post ↔ bush ↔ bush ↔ Lamp post ↔ bush ↔ bush ↔ Lamp post ↔ bush ↔ bush ↔ Lamp post
(a)
Length of each gap
= 21 ÷ 3
= 7
Distance between first and 6th bush
= 7 intervals
= 7 x 7
= 49 m
(b)
Distance between eighth and tenth bush
= 3 intervals
= 3 x 7
= 21 m
(c)
Distance between 2 lamp posts = 21 m
Number of sets of 21 m
= 175 ÷ 21
= 8 r 7
Number of bushes at a distance of 7 m
= 7 ÷ 7
= 1
Number of bushes
= 8 x 2 + 1
= 17
Answer(s): (a) 49 m; (b) 21 m; (c) 17