Lamp posts were located at an equal distance of 12 m apart from one another, starting from the beginning of the road. Between every 2 lamp posts, there were 2 shrubs, planted 4 m apart.
- What was the distance between the first shrub and the 6th shrub?
- What was the distance between the sixth shrub and the fourteenth shrub?
- Given that the stretch of road was 112 m, how many shrubs were there?
Lamp post ↔ shrub ↔ shrub ↔ Lamp post ↔ shrub ↔ shrub ↔ Lamp post ↔ shrub ↔ shrub ↔ Lamp post
(a)
Length of each gap
= 12 ÷ 3
= 4
Distance between first and 6th shrub
= 7 intervals
= 7 x 4
= 28 m
(b)
Distance between sixth and fourteenth shrub
= 12 intervals
= 12 x 4
= 48 m
(c)
Distance between 2 lamp posts = 12 m
Number of sets of 12 m
= 112 ÷ 12
= 9 r 4
Number of shrubs at a distance of 4 m
= 4 ÷ 4
= 1
Number of shrubs
= 9 x 2 + 1
= 19
Answer(s): (a) 28 m; (b) 48 m; (c) 19