The figure shows a pattern formed using some ice-cream sticks.
- How many ice-cream sticks are used to form 20 squares?
- How many squares can be formed using 301 ice-cream sticks?
(a)
Pattern for the number of ice-cream sticks
1 square: 1 x 3 + 1 = 4
2 squares: 2 x 3 + 1 = 7
3 squares: 3 x 3 + 1 = 10
Formula
Number of ice-cream sticks = Number of squares x 3 + 1
Number of ice-cream sticks for 20 squares
= 20 x 3 + 1
= 61
(b)
Number of squares x 3 + 1 = 301
Number of squares x 3 = 301 - 1
Number of squares = 300 ÷ 3
Number of squares = 100
Answer(s): (a) 61; (b) 100