Giải

Số thời gian 1 người thợ đó xây xong bức tường là :

24 × 3 = 72 (phút)

Số thời gian 4 người thợ đó xây xong bức tường là :

72 : 4 = 18 (phút)

Đáp số : 18 phút

1- was

2- were

3- was

4- was

5- was

6- were

7- were

8- were

9- was

10- were