Question 199894
"The ratio of the number of green cubes to the number of red cubes is 2:1"
g = 2r


"She adds 12 more red cubes in the box and the ratio becomes 4:5"
5g = 4(r + 12) ___ 5g = 4r + 48


substituting ___ 5(2r) = 4r + 48 ___ 10r = 4r + 48 ___ 6r = 48 ___ r = 8


(a) g = 2(8) ___ g = 16


(b) r + 12 = 8 + 12 = 20