MathematicsThe ratio of boys and girls in a school is 12:5 . If the number of girls is 840, then the total strength of the school is ____.

The ratio of boys and girls in a school is 12:5 . If the number of girls is 840, then the total strength of the school is ____.

Solution:

The ratio of boys and girls in a school is 12:5 . If the number of girls is 840, then the total strength of the school is 2856.
Given, the ratio of boys and girls in a school is 12:5 and the number of girls is 840.
Let the common ratio be x.
So, total strength=12x + 5x = 17x.
The number of girls=840 = 5x.
x = 168
So the total strength is 17