solve for ...

[Muddy]

dont know why i cant get this ... but I cant seem to solve the following for P4:

M = (( X1 * P1 + X2 * P2 + X3 * P3 + X4 * P4 ) * R ) / ( P1 + P2 + P3 + P4 )

can anyone help me please?

[NotLKH]

dont know why i cant get this ... but I cant seem to solve the following for P4:

M = (( X1 * P1 + X2 * P2 + X3 * P3 + X4 * P4 ) * R ) / ( P1 + P2 + P3 + P4 )

can anyone help me please?

M = (( X1 * P1 + X2 * P2 + X3 * P3 + X4 * P4 ) * R ) / ( P1 + P2 + P3 + P4 )

So

( P1 + P2 + P3 + P4 )*M = (( X1 * P1 + X2 * P2 + X3 * P3 + X4 * P4 ) * R )

So

(P1+P2+P3)*M+P4*M = (X1*P1+X2*P2+X3*P3)*R + X4*P4*R

So:

(P1+P2+P3)*M-(X1*P1+X2*P2+X3*P3)*R = X4*P4*R - P4*M

So:

(P1+P2+P3)*M-(X1*P1+X2*P2+X3*P3)*R = P4*(X4*R-M)

So:

[(P1+P2+P3)*M-(X1*P1+X2*P2+X3*P3)*R]/[X4*R-M]=P4