A rm operates in the short run using labour and physical capital to produce its output. The rm's amount of physical capital is xed. a) Complete the following table, which shows the total product of labour (TPL) associated with various levels of labour use, by lling in the columns for marginal product of labour (MPL) and average product of labour (APL). Labour (number of workers) TPL (units of output) MPL (units of output per addi onal worker) APL (units of output per worker) 0 0 - - 1 15 2 40 3 75 4 100 5 120 6 132 7 140 8 146 9 150 10 150