Mrs Sutiono had $150. She spent 15 percent of the money on groceries, 12 percent of it on a book. How much money had she left?

Mrs Sutiono spent 15/100 x $150 = $<<15/100*150=22.50>>22.50 on groceries.

She spent 12/100 x $150 = $<<12/100*150=18>>18 on a book.
Therefore, Mrs Sutiono had $150 - $22.50 - $18 = $<<150-22.5-18=109.50>>109.50 left. Answer: \boxed{109.50}.