Answer:
The total number of ways are 168.
Step-by-step explanation:
Consider the provided information.
There are 7 junior and 3 senior coders in her group.
The first project can be written by any of the coders. The second project must be written by a senior person and the third project must be written by a junior person.
For second project we have 3 choices and for third project we have 7 choices.
Now there are 2 possible case:
Case I: If first and second coder is senior, then the total number of ways are:
![3\times 2\times 7=42](https://tex.z-dn.net/?f=3%5Ctimes%202%5Ctimes%207%3D42)
Case II: If first and third coder is junior, then the total number of ways are:
![7\times 3\times 6=126](https://tex.z-dn.net/?f=7%5Ctimes%203%5Ctimes%206%3D126)
Hence, the total number of ways are: 42+126=168