Answer:
Third option: 5.48
Step-by-step explanation:
Given the quadratic model that represents the approximate height in meters of the ball 
. the time in seconds x, when the ball is 50 meters from the ground can be calculated by substituting 
and solving for x.
Then:
Subtract 200 from both sides:
Divide both sides by -5:
Apply square root to both sides:
The ball is 50 meters from the ground after about 5.48 seconds.
The more she charges for her cards, the fewer cards she'll have to sell
to recover her start-up costs. So naturally, she wants to charge as much
for each card as she can get away with.
Let's start out assuming she charges the maximum of $1.70 for each one
(and that there are customers willing to pay $1.70 to buy one.)
It costs Gina $0.45 to produce a card, and she sells it for $1.70.
Her profit from selling each card is ($1.70 - $0.45) = $1.25 profit.
How many times does she need $1.25 in profit to get back the $1500
that she sank into the business to get it started ?
($1500) / ($1.25 per card) = 1,200 cards .
That's the minimum number she must sell, and it only works if she
charges the full $1.70 for each card. If she charges a lower price
for them, then she'll need to sell more cards to make up the $1500 .
