Answer:
392.1 mL
Step-by-step explanation:
Ideal gas law says:
PV = nRT
where P is absolute pressure, V is volume, n is amount of gas in moles, R is the universal gas constant, and T is absolute temperature.
If n, R, and T are held constant:
P₁ V₁ = P₂ V₂
Plugging in values:
(745.0 mmHg) (400.0 mL) = (760.0 mmHg) V
V = 392.1 mL