Justin placed 25 pins in a row from one to the other end of a bulletin board at equal distance apart as shown in the diagram. The distance between the first and last pin was 96 cm.
- What was the distance between the first and twelfth pin?
- Justin decided to remove 12 pins and rearrange the remaining pins at a new equal spacing. What was the new distance of each spacing?
(a)
Number of intervals is 1 less than the number of pins.
Number of intervals in 25 pins
= 25 - 1
= 24
24 intervals = 96 cm
1 interval = 96 ÷ 24 = 4 cm
Number of intervals between the first and the twelfth pin = 11
Distance between the first and the twelfth pin
= 11 x 4
= 44 cm
(b)
Number of pins left
= 25 - 12
= 13
Number of intervals
= 13 - 1
= 12
New distance of each spacing
= 96 ÷ 12
= 8 cm
Answer(s): (a) 44 cm; (b) 8 cm