 
<translate> Ka ụmụ nwoke bụrụ X, mgbe ahụ ụmụ nwanyị bụrụ 7X, ngụkọta = X+7X = 8X N'ihi ya, ọ ga-abụ ọtụtụ nke 8, 30 abụghị ọtụtụ nke 8. Azịza ya bụ: (C). <eng> Let the boys are X, then girls are 7X, total = X+7X = 8X
So it should be multiple of 8, 30 is not a multiple of 8.
The final answer: (C). 