Answer:
11 cups
Step-by-step explanation:
Not really a method just started at 10 and then realised deal d was better so go up by one so 11 and c worked out better as I timed 30 by 11 and 15 by 1 + the flat fee.
See below
You know that he spent 1/3 of his earnings, and then 1/4. After this, he has $28.90. You can write the equation like this:
1/4(x * 1/3) = $28.90.
If you need to solve it:
1/4 * 1/3x = 28.90
1/12x = 28.90
x = 346.80
x = 1, x = -1
-4x² = -4
x² = 1
x =
x = ±1