A mixture of 40 liters of paint is 25% red tint, 30% yellow tint and 45% water. 6 liters of yellow tint are added to the original mixture. the percent of yellow tint in the new mixture is?

40 liters ... 30% is yellow tint

0.30 (40) = 12 liters are yellow

if u add 6 liters ... (12 + 6) = 18 liters are now yellow ... and since u added 6 liters, ur total mixture is now 46 liters.

18/46 = 0.39 = 39% <===