Total absent Mon&ndash;Fri = Average × 5 = 3.4 × 5 = 17 pupils.<br><br>
Tue = Wed = Thu = 2 pupils each. Mon is 3 more than Fri.<br><br>
[[model:questions/solutions/q4670.png]]<br><br>
&bull; Let Friday = 1 unit; Monday = 1 unit + 3<br>
&bull; Total = (1 unit + 3) + 2 + 2 + 2 + 1 unit = 2 units + 9 = 17<br>
&bull; 2 units = 17 − 9 = 8<br>
&bull; 1 unit = 4 (Friday)<br>
&bull; Monday = 4 + 3 = 7 pupils<br><br>
7 pupils were absent on Monday.<br>
Check: Mon 7 + Tue 2 + Wed 2 + Thu 2 + Fri 4 = 17. 17 ÷ 5 = 3.4. ✓