In a school canteen, chairs are arranged around a rectangular table as shown below. <br> When 2 tables are joined together in a horizontal line, the chairs are arranged as shown below. <hr> How many chairs are needed if 4 tables are joined together in a horizontal line? <br> How many chairs are needed if 15 tables are joined together in a horizontal line? <br> <input min="0" type="number" id ="imp5pg027q13_1" class="lineinput" placeholder="?" /> chairs are needed if 4 tables are joined. <br> <input min="0" type="number" id ="imp5pg027q13_2" class="lineinput" placeholder="?" /> chairs are needed if 15 tables are joined.