We need to create a table as follows:
Yellow pieces Green pieces Yellow/Green
5 50 - 5 = 45 5/45 = 0.11
10 50 - 10 = 40 10/40 = 0.225
15 50 - 15 = 35 15/35 = 0.4286
25 50 - 25 = 25 25/25 = 1
35 50 - 35 = 15 35/15 = 2.333
45 50 - 45 = 5 45/5 = 9
We define the number of yellow pieces, then we calculate the number of green pieces taking into account that the sum of yellow and green is 50.
Finally, we found the relation between yellow and green pieces. The answer is going to be the row where the division between the yellow and green pieces is 9. Because that division tells us how many Yellow pieces are for every green piece.
Answer: 45 yellow pieces