You divide each side of the equation by 'a', and you immediately have
the value of 'x' in terms of 'a and 'b'.
If his employee pays 90%, then Ricardo pays 10%
so the plan was 550......Ricardo paid : 0.10(550) = $ 55 per month
now the plan is 700....Ricardo will pay : 0.10(700) = $ 70 per month
so Ricardo will pay : (70 - 55) = $ 15 more per month <===
7 cups - 2 cups = 5 cups of flour
