At the beginning of a week, a stock’s price is $9.40 per share. for that entire week, the stock’s price decreased at a steady rate of $0.20/day. christine graphs the price of the stock versus time. she plots the price of the stock along the vertical axis, and she plots time in days along the horizontal axis. what is the y-intercept of the line?

I presume you had a typo so I will presume you meant:

3000km with 3 friends
6 liters per 100 km
1 liter costs $1.20

Now let's calculate:

6l/100km means 6x30 for 3000km so we have a total fuel consumption of 180 liters for the total of 3000km

180 x $1.20 = $216 total

Dividing the total cost with 3:

$216 / 3 = $72 per friend!

That is the equal amount of money each friend has to chip in!