. How many yellow jelly beans were originally in the dish?

Question

If the ratio of red jelly beans and yellow jelly beans is 3:4. If Greg eats 3 red and 6 yellow and the ratio is 4:5. How many yellow jelly beans were originally in the dish?

Answer 1

r : y :: 3 : 4

4r = 3y

 

r - 3 : y - 6 :: 4 : 5

5(r - 3) = 4(y - 6)

5r - 15 = 4y - 24

 

4r - 3y = 0

5r - 4y = -9

 

Can you solve the system?