Question 1128390
{{{ highlight( 10 ) }}} and {{{ highlight( 10 ) }}}

Product = {{{ highlight( 100 ) }}}
——

Workout:
A+B = 20
P = AB = A(20-A)

dP/dA = 20-2A  
dP/dA = 0 = 20 - 2A  —>  A=10 —> B=10

{{{d^2P/dA^2 = -2  }}} so the function is concave down and the value found above for A is maximal.