Correct option is D
Let 6x be the number of boys and 5x be the number of girls in the school.
6x+5x=1650
11x=1650
x=150
So, the number of boys is:6x=6×150=900
And the number of girls is:5x=5×150=750
The new number of boys = 900+124=1024
g= 18
Ratio= 18: 124= 9 : 62