6/10 is the answer but if you want it simplified the the answer would be 3/5.
Divide 1500 by 5 to get one fifth of the savings. Multiply that by 12 to get yearly savings. You end up with 3600.
Answer: 8 textbooks
Step-by-step explanation:
Sold 40 notebooks = 40 x $4 = $160
$800 - $160 = $640 left to sell
$640/$80 (cost of textbook) = 8 textbooks need to be sold