If (a³ + b³ + c³ - 3abc) = 405, and (a - b)² + (b - c)² + (c -a)² = 54, find the value of (a + b + c).

What is the surface area (in cm²) of a spherical sculpture whose radius is 35 cm? (Take π = $\frac{22}{7}$)

Pipe A can fill 50% of the tank in 6 hours and pipe B can completely fill the same tank in 18 hours. If both the pipes are opened at the same time, in how much time (in minutes) will the empty tank be completely filled?

A 9-digit number 846523X7Y is divisible by 9, and Y - X = 6. Find the value of $\rm\sqrt{2X+4Y}$.