Answer:
[tex]\boxed{\text{30 800 people}}[/tex]
Step-by-step explanation:
1. Area of the crowd
The crowd fills a rectangle that is 2 mi long and 7 ft wide.
(a) Convert miles to feet.
[tex]\text{l} = \text{2 mi} \times \dfrac{\text{5280 ft}}{\text{1 mi}} = \text{10 560 ft}[/tex]
(b) Calculate the area
A = lw = 10 560 ft × 7 ft = 73 920 ft²
2. Size of crowd
15 people occupy an area of 6 ft × 6 ft = 36 ft²
[tex]\text{Size of crowd} = \text{73 920 ft}^{2}\times \dfrac{\text{15 people}}{\text{36 ft}^{2}} = \textbf{30 800 people}\\\text{The size of the crowd is $\boxed{\textbf{30 800 people}}$}[/tex]