Answer:
He earned for washing 30 windows this month = $960.
Step-by-step explanation:
Greg earned $900 for washing 30 windows.
Earning per window = 900/30 = $30
He increased the wage by $2 per window.
Earning per window this month = $32
He earned for washing 30 windows this month = 30 *32 =$960.
Thank you.