Solution:

Given:
- Charge q is at the center of two concentric spheres.
- The outward electric flux through the inner sphere is
- The outward electric flux through the outer sphere is 20.

To find:
- The amount of charge contained in the region between the two spheres.

Let's analyze the problem step by step:

1. Electric Flux:
- Electric flux is a measure of the electric field passing through a given area.
- It is given by the formula Φ = E * A * cos θ, where E is the electric field, A is the area, and θ is the angle between the electric field and the normal to the area.
- The electric flux passing through a closed surface is equal to the total charge enclosed by that surface divided by the permittivity of free space (ε0).

2. Flux through the inner sphere:
- The electric flux through the inner sphere is given as Φ1.
- Since the charge q is at the center of the spheres, the electric field at any point on the inner sphere due to q will be radial and directed outward.
- Hence, the electric field and the normal to the inner sphere will be parallel, making the angle θ = 0°.
- Therefore, the electric flux through the inner sphere can be written as Φ1 = E * A1 * cos 0° = E * A1.

3. Flux through the outer sphere:
- The electric flux through the outer sphere is given as Φ2.
- The electric field at any point on the outer sphere due to q will also be radial and directed outward, similar to the inner sphere.
- Hence, the electric field and the normal to the outer sphere will also be parallel, making the angle θ = 0°.
- Therefore, the electric flux through the outer sphere can be written as Φ2 = E * A2 * cos 0° = E * A2.

4. Relationship between the fluxes:
- According to Gauss's Law, the total electric flux through a closed surface is equal to the total charge enclosed by that surface divided by the permittivity of free space (ε0).
- Since both spheres enclose the same charge q, we can write the relationship as Φ1 + Φ2 = q/ε0.

5. Given information:
- It is given that the electric flux through the inner sphere is Φ1 =
- It is also given that the electric flux through the outer sphere is Φ2 = 20.

6. Using the relationship between the fluxes:
- Substituting the given values into the relationship, we get
- Solving this equation, we find q =

7. Conclusion:
- The amount of charge contained in the region between the two spheres is q.

Therefore, the answer is q.