Signal mistakenly produced 1,000 defective cell phones. the phones cost $60 each to produce. a salvage company will buy the defective phones as they are for $30 each. it would cost signal $80 per phone to rework the phones. if the phones are reworked, signal could sell them for $120 each. assume there is no opportunity cost associated with reworking the phones. compute the incremental net income from reworking the phones.