Brittany has $250. She spent $78 on a tattoo. She spent $12 on dinner. What fraction of the money does she have left?

Brittany spent a total of $78 + $12 = $<<78+12=90>>90.

Thus, Brittany has $250 - $90 = $<<250-90=160>>160 left.
Hence, the fraction of the money Brittany has left is $160/$250 = $\boxed{\frac{16}{25}}.

To find out what fraction of the money Brittany has left, we need to subtract the amount she spent from the amount she initially had.

Brittany initially had $250.
She spent $78 on a tattoo and $12 on dinner.
So, she spent a total of $78 + $12 = $90.

To find out how much money Brittany has left, we subtract the amount she spent from what she initially had: $250 - $90 = $160.

Therefore, Brittany has $160 left.

To express this as a fraction, we use the amount she has left ($160) as the numerator and her initial amount ($250) as the denominator: $160/$250.

This fraction cannot be simplified any further, so the answer is $160/$250.