 
<translate> A. 13 (enwere ike ịtụ ya site n'idebe ịdị arọ nke 10, 2 na 4) B. 15 (enweghị ike ịtụ ya) C. 17 (a pụrụ ịtụ ya site n'idebe ịdị arọ nke 10 na 7 kg) D. 19 ((enwere ike ịtụ ya site na ijide ịdị arọ nke 10, 2 na 7 kg) E. 21 (enwere ike ịtụ ya site n'ịdebe ịdị arọ nke 10, 7 na 4 kg) Ya mere azịza ikpeazụ bụ (B). <eng> A. 13 (can be weighed by keeping weights of 10, 2 and 4 )
B. 15 (cannot be weighed)
C. 17 (can be weighed by keeping weights of 10 and 7 kg)
D. 19(can be weighed by keeping weights of 10, 2 and 7 kg)
E. 21 (can be weighed by keeping weights of 10, 7 and 4 kg) So the final answer is (B). 