There are 71 rows of seats in a,lecture hall.each row has,38 seats 
That's 38 seats per row times 71 rows = 2698 seats, so there are 2698
students in all. 
the girls take up 281 of the seats 
2698 seats - 281 girl's seats = 2417 seats for boys. 
How many boys are in the lecture hall?
2417 boys.
Wow!  That's more that 8 1/2 times as many boys as girls!
Are you sure you have those given numbers right?
Edwin