 
<translate> E nwere ụmụ klas nke ise 109 + ụmụ klas nke isii 115 + ụmụ klas nke asaa 118 = ụmụ akwụkwọ 342 na-aga njem ahụ. Enwere ndị nkuzi 4 + nne na nna 2 = ndị okenye 6 na-aga njem mmụta maka ọkwa ọ bụla. E nwere klas 3 na-aga, yabụ klas 3 x ndị okenye 6 / ọkwa = 18 ndị okenye niile na-aga njem ahụ. Ụmụakwụkwọ 342 + ndị okenye 18 = mmadụ 360 na-aga njem ahụ. Ya mere, mmadụ 360 / oche 72 = bọs ise. N'ihi ya, azịza ya bụ 5. <eng> There are 109 fifth graders + 115 sixth graders + 118 seventh graders = 342 students going on the trip. There are 4 teachers + 2 parents = 6 adults going on the field trip for each grade. There are 3 grades going, so 3 grades x 6 adults / grade = 18 total adults going on the trip. There are 342 students + 18 adults = 360 people going on the trip. So, 360 people / 72 seats = 5 buses.
Thus, the answer is 5. 