How will the electrical capacity of a flat air capacitor change when the distance between its plates

How will the electrical capacity of a flat air capacitor change when the distance between its plates is doubled and a dielectric with a permittivity of 4 is introduced between the plates?

d2 = 2 * d1.
ε = 4.
S1 = S2.
C2 / C1 -?
The electrical capacity of a flat air condenser is determined by the formula: C = ε0 * ε * S / d. Where ε0 is the electrical constant, ε is the dielectric constant of the dielectric, S is the area of the capacitor plates, d is the distance between the capacitor plates.
C1 = ε0 * S / d1.
C2 = ε0 * ε * S / d2 = ε0 * 4 * S / 2 * d1 = 2 * ε0 S / d1 = 2 * C1.
C2 / C1 = 2.
Answer: the electrical capacity of a flat air condenser will double.