 
<translate> Nke mbụ, chọpụta ọnụ ọgụgụ marbles na-acha akwụkwọ ndụ: 20 marbles na-acha odo odo / 2 = 10 marbles na-acha akwụkwọ ndụ. Mgbe ahụ chọpụta ole marbles na-acha ọbara ọbara ma ọ bụ na-acha anụnụ anụnụ: 60 marbles - 20 odo marbles - 10 green marbles = 30 marbles. Kewaa nọmba a n'etiti iji chọpụta ole marbles na-acha anụnụ anụnụ: 30 marbles / 2 = 15 marbles na-acha anụnụ anụnụ. N'ikpeazụ, kewaa ọnụ ọgụgụ marbles na-acha anụnụ anụnụ site n'ọnụ ọgụgụ marbles nile ma mụbaa ya site na 100 iji chọta pasent ohere nke inweta marble na-acha anụnụ anụnụ: 15 marbles / 60 marbles * 100 = 25%. N'ihi ya, azịza ya bụ 25. <eng> First find the number of green marbles: 20 yellow marbles / 2 = 10 green marbles. Then find how many marbles are either red or blue: 60 marbles - 20 yellow marbles - 10 green marbles = 30 marbles. Divide this number in half to find how many marbles are blue: 30 marbles / 2 = 15 blue marbles. Finally, divide the number of blue marbles by the total number of marbles and multiply by 100 to find the percentage chance of getting a blue marble: 15 marbles / 60 marbles * 100 = 25%.
Therefore, the answer is 25. 