Final answer:
Lisa can buy 7 DVDs without exceeding her $100 budget.
Step-by-step explanation:
To find out how many DVD's Lisa can buy without exceeding her $100 budget, we need to consider the cost of the DVDs and the shipping. Each DVD costs $11.99 and the shipping for the whole order is $9.99. We need to subtract the cost of shipping from Lisa's budget first: $100 - $9.99 = $90.01. Next, we need to find out how many DVDs Lisa can buy with $90.01. Since each DVD costs $11.99, we can divide $90.01 by $11.99 to find out how many DVDs she can buy: $90.01 ÷ $11.99 = 7.