Question 993429
Hi there,
1) 2 + $0.50x = $3.50
 $0.50x = $3.50 - $2
 $0.50x = $1.50
 x = $1.50/$0.50
 x = 3
3 Children.
2) 2 numbers 
use x + 2x
x + 2x = 72
3x = 72
x = 72/3
x = 24
Numbers are 24 and 48
3) Steve's amount of work - 12x
  Ryan's amount of work = 14x + 10
12x + 14x + 10 = $3520
28x + 10 = $3520
28x = $3520 - 10
28x = $3510
x = $135
Steve earned 12(135) = $1620
Ryan earned 14(135) + 10 = $1900
Hope this helps :-)