4. Alloy $A$ of two metals with a mass of 6 kg, in which the first metal is twice as much as the second, placed in a container with water, creates a pressure force on the bottom of $30 \mathrm{N}$. Alloy $B$ of the same metals with a mass of 3 kg, in which the first metal is five times less than the second, placed in a container with water, creates a pressure force on the bottom of $10 \mathrm{N}$. What pressure force (in newtons) will a third alloy, obtained by melting the initial alloys, create?

$\{40\}$