Question

to make green paint,the store mixes yellow and blue in the ratio 2:3. if they used 15 litres of yellow paint, how much blue paint did they use

Answer 1

2:3 is only the most simplified ratio, and since the store used 15 liters of paint, 15/3 = 5 liters of paint. That means 5 * 2 = 10  cans of blue paint.