There were 50 dollars in Olivia's wallet. She collected 19 more dollars from an atm. After she visited a supermarket there were 8 dollars left. How much more money did she spend at the supermarket than she collected at the atm?
Olivia had 50 dollars in her wallet. 
She collected 19 more dollars from an ATM. 
That means she had 50 + 19 = 69 dollars. 
After she visited the supermarket, she had 8 dollars left. 
That means she spent 69 - 8 = 61 dollars at the supermarket. 

So she spent 61 - 19 = 42 dollars more at the supermarket than she collected at the ATM.