Class Activity Inequalities

1.You want to invest$30,000. Part of this will be invested in a stable2%-simple-interest rate account. The remainder will be "invested" in your friend's new phone app, and he says that he'll pay you back with4%interest. What is the least you can "invest" with your friend, and still (assuming he really pays you back) get at least$1000in interest?

2.Checking account balance: If the average daily balance in a certain checking account drops below $1000, the bank charges the customer a $7.50 service fee. The table gives the daily balance for one customer. What must the daily balance be for Friday to avoid a service charge?

Weekday

Balance

Monday

$1125

Tuesday

$850

Wednesday

$625

Thursday

$400

3.A company has fixed costs of $12000 a month and variable costs of $10 per unit.They sell their product for $35. What is the level of production and sales needed in a month in order to make a profit?