3:4
(b) The ratio of boys to girls in a school is
There are 120 more girls than boys.
How many students are in the school?
Answers
Answer:
Ratio:
Boys : Girls
3 : 4
Let number of Boys = x
Number of girls = x + 120
x/x+120 = 3/4
=> 4x = 3x + 360
=> x = 360
Boys = 360
Girls = 480
Total students = 840
______________
Correct question:
(b) The ratio of boys to girls in a school is 3:4. There are 120 more girls than boys. How many students are in the school?
Answer:
The number of students in the class is 840.
Given:
The ratio of boys in the class is 3:4.
The number of girls is more than the number of boys by 120.
To find:
The number of students in the school.
Explanation:
Let, the common multiple of the ratio be, 'n'.
So, the number of boys = (n×3)
= 3n.
Similarly, the number of girls = (n×4)
= 4n.
According to the problem:
(4n - 3n) = 120.
⇒ n = 120.
∴ Total number of boys in the class _
(120×3)
= 360.
∴Total number of girls in the class_
(120×4)
= 480.
∴ Total number of students in the class_
(360+480)
= 840 students.
∴ There are 840 students in the class.