Fixed and Variable Factory Overhead Rates; Over$-$ or Underapplied Amount. Normal operating capacity of Robertson Inc. is $100,000$ machine hours per month, the level usec to compute the predetermined factory overhead application rate. At this level of activits. fixed factory overhead is estimated to be $$150,000,$ and variable factory overhead is esti mated to be $$250,000.$ During March, actual production required $105,000$ machine hour $-$ and actual factory overhead totaled $$411,000.$Required: $(1)$ Determine the fixed portion of the factory overhead application rate.$(2)$ Determine the variable portion of the factory overhead application rate.$(3)$ Is factory overhead for March over$-$ or underapplied, and by how much?