Eugene sold his tarts to earn allowance during school vacation. The number of $2, $5 and $10-notes she earned were in ratio of 3 : 7 : 5. The notes were worth $2821 altogether. How many $2-notes were there?

Anna sold her muffins to earn allowance during school vacation. The number of $2, $5 and $10-notes she earned were in ratio of 5 : 3 : 2. The notes were worth $1125 altogether. How many $2-notes were there?

Students are donating money to a charity fund that helps less privileged kids. The number of $2, $5 and $10-notes donated are in the ratio of 9 : 2 : 5.49 of the $2-notes and 10 $5-notes are taken out. The remaining notes are worth $300. How many $10-notes are there?

The ratio of the number of $5-notes to the number of $10-notes is 5 : 6. When four $5-notes were exchanged for $10-notes, the ratio became 8 : 13. How much money was there?

Mr Tan saved $716 from his salary. He gave half of the remaining to his 4 children equally and contributed the rest to charity. Each child received $m. How much was his salary?

Jason and Lisa had some money in their bank. After Jason and Lisa managed to save $189 and $81 respectively, the amount of money Jason had was twice of Lisa. If initially, the money Jason and Lisa had in the bank were in the ratio 5 : 7, how much did Jason have after saving?