The population in a school has a boy to girl ratio of 4 boy: 5 girls. If there are 85 gi
in the school, how many are boys? Round to nearest whole boy
To find the number of boys in the school, we need to calculate the ratio of boys to the total number of students.
The total ratio of boys to girls is 4 boys: 5 girls.
To find the total ratio, we need to find the total number of students in the school. Since each student represents one unit in the ratio, we add the number of boys and girls together.
Total number of students = number of boys + number of girls
Total number of students = 4 boys + 5 girls
Given that there are 85 girls in the school, we can substitute this value into the equation:
Total number of students = 4 boys + 5(85)
Total number of students = 4 boys + 425
To find the number of boys, we need to isolate the variable:
4 boys = Total number of students - 425
To calculate the total number of students, we can divide 85 by the ratio of girls to the total ratio of students:
Total number of students = 85 girls / (5 girls / (4 boys + 5 girls))
Total number of students = (85 girls / 5 girls) * (4 boys + 5 girls)
Total number of students = 17 * (4 boys + 5 girls)
Total number of students = 68 boys + 85 girls
Now we can substitute the total number of students back into the equation:
4 boys = (68 boys + 85 girls) - 425
4 boys = 68 boys + 85 girls - 425
4 boys = 68 boys + 85(85) - 425
4 boys = 68 boys + 7225 - 425
4 boys = 68 boys + 6800
4 boys - 68 boys = 6800
-64 boys = 6800
boys = 6800 / -64
Using the equation, we get the number of boys in the school, we calculate:
boys = 6800 / -64
boys ≈ -106.25
Since we cannot have a fractional part of a boy, we round the solution to the nearest whole number:
boys ≈ -106
Hence, there are approximately -106 boys in the school.