In one week a computer store sold a total of 35 computers and hard drives. The revenue from these sales was $19,170.00. The computers sold for $750.00 per unit and the hard drives sold for $160.00 per unit. Use x for the number of computers sold and y for the number of hard drives sold. Its asking me to make a mathematical equation for the combined number of computers and hard drives sold . Then to make a mathematical expression for the amount of revenue from the sales. How many hard drives did the store sell ? Can I get some help please ?