4. Automotive Trades At the beginning of the day on Monday, the parts
department has on hand 520 spark plugs. Mechanics in the service depart-
ment estimate they will need about 48 plugs per day. A new shipment of
300 will arrive on Thursday. Write out a mathematical statement that gives
the number of spark plugs on hand at the end of the day on Friday. Calcu-
late this total.
StS estimate