We are given to find
the experimental probability that a 10th-grade student chosen at random has at least one, but no more than two, siblings
we know that
probability = ( number of favourable outcomes)/ ( total possible outcomes)
a 10th-grade student chosen at random has at least one, but no more than two, siblings
so, there can be one or two siblings
so, total number of such students =18+10=28
Number of favourable outcomes =28
total number of students =4+18+10+8=40
so, total favourable outcomes =40
now, we can find probability
So,
the experimental probability is 70%...........Answer