The original price of the machine is $2,600 but it has a depreciation value now of $1,200.
*original price - depreciation value = machine's existing value*
$2,600 - $1,200 = $1,400
However, they've sold the machine for $2,200 instead of 1,400 (which is supposedly the existing price). So, they've gain $800 ($2,200 deducted by $1,400) out from this transaction.