Look at the figures. The rectangles represent tables and the dots represent chairs for guests at a gathering.
- How many tables will Figure 4 have?
- How many chairs will Figure 13 have?
- If there are 90 guests at the gathering, how many tables will be needed?
(a)
Pattern for the number of tables
Figure 1: 1
Figure 2: 2
Figure 3: 3
Formula
Number of tables = Figure number
Number of tables for Figure 4 = 4
(b)
Pattern for the number of chairs
Figure 1: 1 x 4 + 2 = 6
Figure 2: 2 x 4 + 2 = 10
Figure 3: 3 x 4 + 2 = 14
Formula
Number of chairs = Figure number x 4 + 2
Number of chairs for Figure 13
= 13 x 4 + 2
= 54
(c)
90 guests: 90 chairs
Figure number for 90 chairs
= (90 - 2) ÷ 4
= 22
Number of tables for Figure 22 = 22
Answer(s): (a) 4; (b) 54; (c) 22