At first, the number of boys and the number of girls on a school bus were the same.<br>Then 30% of the boys and 20% of the girls alighted at the bus stop.<hr> If the number of children who had alighted from the bus was 10, how many pupils were there on the bus at first? <br> <input min="0" type="number" id ="imp6pg114q2b_1" class="lineinput" placeholder="?" />