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?

To solve this problem, we need to follow these steps:

1. First, we need to understand the ratio of the notes. The ratio of $2,$5, and $10 notes is 9:2:5. This means for every 9$2-notes, there are 2 $5-notes and 5$10-notes.

2. We know that 49 of the $2-notes and 10$5-notes are taken out. We need to subtract these from the total value of the remaining notes, which is $300. So, 49$2-notes equals $98 and 10$5-notes equals $50. Subtracting these from$300 gives us $152.

3. Now, we need to find out how many notes make up this $152. Since the ratio of the notes is 9:2:5, we can set up the equation 2x + 5x + 10x = 152, where x is the number of sets of notes in the ratio 9:2:5. Solving for x gives us x = 8.

4. Finally, we need to find out how many $10-notes there are. Since the ratio of$10-notes to the total number of notes is 5, we multiply 5 by the number of sets of notes, which is 8. So, there are 5 * 8 = 40 $10-notes.