A $6\mathrm{.}00-kg$ block is in contact with a $4\mathrm{.}00-kg$ block on a rough surface as shown in the

figure. Total friction force acts on the blocks is $10N.$ The $6\mathrm{.}00-kg$ block is being

pushed by a horizontal $20\mathrm{.}0-$N force as shown. What is the magnitude of the force

that the $6\mathrm{.}00-kg$ block exerts on the $4\mathrm{.}00-kg$ block?

$($The coefficients of friction for both blocks are the same$)$

A$)20\mathrm{.}0NB$