there are 3 boys for every 4 girls.how many are boys in a class of 42?
3 + 4 = 7
42 / 7 = 6
Boys : 6 * 3 = 18
Girls : 4 * 6 = 24
let the number of boys be 3x and the number of girls be 4x
2x+4x = 42
7x=42
x=6
so we have 3x or 18 boys and 4x or 24 girls.
To determine the number of boys in a class of 42, we need to use the given ratio of 3 boys to 4 girls.
Step 1: Calculate the total number of parts in the ratio.
The total number of parts in the ratio is 3 + 4 = 7.
Step 2: Divide the total number of boys by the total number of parts and multiply by the total number of students.
Since there are 42 students in the class, the number of boys can be calculated as:
(3/7) * 42 = (3 * 42) / 7 = 18.
Therefore, there are 18 boys in a class of 42.