Claire and Clive mow lawns for $25. Their company already has $250 in its bank account, but they are trying to save up till $900.
how many lawns will they need to mow to reach their goal?
To reach their goal, they need to earn a total of $900 - $250 = $<<900-250=650>>650.
Since they earn $25 per lawn, they will need to mow $650 รท $25 = <<650/25=26>>26 lawns. Answer: \boxed{26}.