9 Sarah is awake for 100 hours per week. Using one diagram, show Sarah's budget constraints if she earns $12 per hour, $16 per hour and $20 per hour. Now draw indifference curves such that Sarah's labour supply curve is upward-sloping when the wage is between $1 2 and

$16 per hour, and backward-sloping when the wage is between $16 and $20 per hour.