Red, blue and green balls are in ratio 2:3:5. If 15 red, 10 blue and an unknown number of green balls are added, the ratio becomes 3:4:6. How many green balls were added?

উত্তর দেখান ও ব্যাখ্যা

উত্তর: (D) 0

ব্যাখ্যা

(2k + 15)/(3k + 10) = 3/4 gives k = 30; green must be 150 = 5k, so 0 are added.