Answer:
The total number of pupils and their teachers = 530
Step-by-step explanation:
No. of girls in the school = 280
The ratio boys to girls is 3:4 and that of teachers to girls is 1:7
∴ The ratio boys to girls is 3x : 4x where, 4x = 280
and The ratio of teachers to girls is x : 7x where, 7x = 280
4x = 280
= x
70 = x
So, the no. of girls in the school = 4x = 4(70) = 280 and the no. of boys in the school = 3x = 3(70) = 210
7x = 280
= x
40 = x
So, the no. of girls in the school = 7x = 7(40) = 280 and the no. of teachers in the school = x = 40
∴ The total number of pupils and their teachers = 280 + 210 + 40
= 530