12.2 is a rational number because you can write it as a fraction.
Hope this answered your question.
Let x = pounds of $12 per pound coffee
then
20-x = pounds of $9 per pound coffee
.
12x + 9(20-x) = 10(20)
12x + 180 - 9x = 200
3x + 180 = 200
3x = 20
x = 20/3
x = 6 and 2/3 pounds of $12 per pound coffee
.
Amount of $9 per pound coffee:
20-x = 20-20/3 = 60/3 - 20/3 = 40/3
or
13 and 1/3 pounds of $9 per pound coffee
First you’ll multiply to get 3x2x2 + 4x3. Then add them together. 12+12=24