Answer:
3 red buckets and 4 green buckets
Explanation:
You make two equations, one that shows the number of buckets and one that shows the number of liters. We'll make x = the red buckets and y = the green buckets.
x + y = 7 --> This is our first equation, it shows us that x number of red buckets + y number of green buckets equal 7 total (since Roxanne bought 7 buckets).
4x + 3y = 24 --> This is our second equation, it shows us that 4 liters of x number of red buckets + 3 liters of y number of green buckets equals 24 liters total (since her buckets will hold 24 liters in total)
Now that you have identified the two equations, you can solve for variable in equation one, then plug the new equation into equation 2:
x + y = 7 --> y = 7 - x <-- PLUG THIS into the y value of 4x + 3y = 24
4x + 3(7 - x) = 24 <-- SOLVE --> x = 3 <-- NOW WE KNOW THAT THERE ARE 3 RED BUCKETS
plug 3 in for x in the first equation --> 3 + y = 7 --> y = 4
So now we know that there are 3 red buckets, and 4 green buckets.