Because 640s is the relationship between s square miles and acres, so :
color(green)(a= 640)
color(green)(s=7.5) square miles.
(*Since Pam owns color(blue)7.5 square miles, so color(blue)7.5 becomes color(red)s .)
Therefore, we would do:
color(red)(640*7.5)
Because when a number is with a variable(color(purple)(640s), this means it's color(purple)640 times the variable. So for this case it would be : (as color(magenta)7.5 is color(red)s)
color(orange)(640 * s = 640*7.5 = 4800) acres
So Pam owns color(blue)(4,800) acres.
