AMC 12 2025a Problem 2

A box contains $10$ pounds of a nut mix that is $50$ percent peanuts, $20$ percent cashews, and $30$ percent almonds. A second nut mix containing $20$ percent peanuts, $40$ percent cashews, and $40$ percent almonds is added to the box resulting in a new nut mix that is $40$ percent peanuts. How many pounds of cashews are now in the box?

\textbf{(A)}~3.5 \textbf{(B)}~4 \textbf{(C)}~4.5 \textbf{(D)}~5 \textbf{(E)}~6