At \(T\)(K), the pressure of two ideal gases \(A\) and \(B\) is in the ratio
\[
P_A:P_B=2:5.
\]
At this temperature, their densities are the same. The molar mass ratio
\[
(M_A:M_B)
\]
is
Show Hint
For an ideal gas,
\[
\boxed{
\rho=\frac{PM}{RT}.
}
\]
At the same temperature, if two gases have equal densities,
\[
\boxed{
P_1M_1=P_2M_2.
}
\]