Answer: The salesperson must sell 20 memberships to make the same amount of money under both plans.
Explanation:
Let x be the number of memberships.
In first plan,
Weekly salary of $300 plus a commission of $15 for each membership sold.
i.e. Earning (weekly) = 300+15x
In second plan,
The other plan offers no salary but pays $30 commission on each membership sold.
i.e. earning = 30x
According to the question, when
![300+15x=30x](https://img.qammunity.org/2021/formulas/mathematics/high-school/e8wyfgsbkho0smaw2pzlcdfhba0jv4vshe.png)
![\Rightarrow\ 300=30x-15x\\\\\Rightarrow\ 300=15x\\\\\Rightarrow\ x=(300)/(15)\\\\\Rightarrow\ x=20](https://img.qammunity.org/2021/formulas/mathematics/high-school/kxtbrf4rkchv6nvj9lahez9600e5c8jji9.png)
Hence, the salesperson must sell 20 memberships to make the same amount of money under both plans.