You can use a pivot table.
But if you prefer with tables:
<table border="1" cellspacing="0" style="font-family:Calibri,Arial; font-size:11pt; background-color:#ffffff; "> <colgroup><col style="font-weight:bold; width:30px; " /><col style="width:76.04px;" /><col style="width:79.84px;" /><col style="width:76.04px;" /><col style="width:76.04px;" /><col style="width:79.84px;" /><col style="width:87.45px;" /></colgroup><tr style="background-color:#cacaca; text-align:center; font-weight:bold; font-size:8pt; "><td > </td><td >A</td><td >B</td><td >C</td><td >D</td><td >E</td><td >F</td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >1</td><td >Task</td><td >Employee</td><td >Hours</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >2</td><td >Task 1</td><td >Andrew A</td><td style="text-align:right; ">5</td><td > </td><td >Employee</td><td >Total Hours</td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >3</td><td >Task 2</td><td >Andrew B</td><td style="text-align:right; ">6</td><td > </td><td >Andrew A</td><td style="text-align:right; ">50</td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >4</td><td >Task 3</td><td >Andrew C</td><td style="text-align:right; ">12</td><td > </td><td >Andrew B</td><td style="text-align:right; ">26</td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >5</td><td >Task 4</td><td >Andrew D</td><td style="text-align:right; ">20</td><td > </td><td >Andrew C</td><td style="text-align:right; ">32</td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >6</td><td >Task 5</td><td >Andrew A</td><td style="text-align:right; ">20</td><td > </td><td >Andrew D</td><td style="text-align:right; ">35</td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >7</td><td >Task 6</td><td >Andrew B</td><td style="text-align:right; ">8</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >8</td><td >Task 7</td><td >Andrew C</td><td style="text-align:right; ">10</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >9</td><td >Task 8</td><td >Andrew D</td><td style="text-align:right; ">10</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >10</td><td >Task 9</td><td >Andrew A</td><td style="text-align:right; ">25</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >11</td><td >Task 10</td><td >Andrew B</td><td style="text-align:right; ">12</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >12</td><td >Task 11</td><td >Andrew C</td><td style="text-align:right; ">10</td><td > </td><td > </td><td > </td></tr><tr style="height:19px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >13</td><td >Task 12</td><td >Andrew D</td><td style="text-align:right; ">5</td><td > </td><td > </td><td > </td></tr></table><br /><table style="font-family:Arial; font-size:10pt; border-style: groove ;border-color:#00ff00;background-color:#fffcf9; color:#000000; "><tr><td ><b></b></td></tr><tr><td ><table border = "1" cellspacing="0" cellpadding="2" style="font-family:Arial; font-size:9pt;"><tr style="background-color:#cacaca; font-size:10pt;"><td >Cell</td><td >Formula</td></tr><tr><td >F3</td><td >=SUMIF(EMP_TASK[Employee],[Employee],EMP_TASK[Hours])</td></tr></table></td></tr></table>