Answer: 3 pints left
Explanation:
They had 18 pints of blue paint and they used some for flames and some for sparks.
The total they used for Flames was half of the 18 or 1/2 so that is:
= 18 * 1/2
= 9 pints for flames
Then they used 1/3 for sparks:
= 1/3 * 18
= 6 pints for sparks
Pints left is therefore:
= 18 - 9 - 6
= 3 pints left