9514 1404 393
Answer:
7
Explanation:
The number of red apples (r) in terms of the number of days (d) is ...
r = 20 -2d
The number of yellow apples (y) in terms of the number of days (d) is ...
y = 28 -3d
Using the first equation to write and expression for d, we can substitute into the second equation.
r -20 = -2d
(20 -r)/2 = d . . . . from the first equation
Then ...
y = 28 -3(20 -r)/2 = 28 -30 +3/2r = (3/2)r -2
For 6 red apples left, the number of yellow apples left is ...
y = (3/2)(6) -2 = 7
7 yellow apples will be left when 6 red apples are left.