Answer:
5.92 *10^-6 C
Step-by-step explanation:
For the two charges q3 the force between them is given by

Now we know that
F = 48.1 N, d = 0.0809 m, and k = 8.99 *10^9 kg⋅m^3⋅s^−2⋅C^-2; therefore, the above gives


Now we solve for q_3.
Dividing both sides by 8.99 * 10^9 gives

multiplying both sides by (0.0809)^2 gives

finally, taking the square root of both sides gives
![\sqrt[]{(48.1)/((8.99*10^9))*(0.0809)^2}=√((q_3)^2)](https://img.qammunity.org/2023/formulas/physics/college/408u8vyzz6t7krsvs9bthe2rwr0q8a8mqz.png)
![q_3=\sqrt[]{(48.1)/((8.99*10^9))*(0.0809)^2}](https://img.qammunity.org/2023/formulas/physics/college/k7cutwl4fz34jg2vgfxruplz1dgha5fdeh.png)
Evaluating the right-hand side gives

Hence, the charge q_3 is 5.92 x 10^-6 C.