the ratio of the number of boys to the number of girls in a class is 5:4. if there are 15 boys, how many girls are there
b = number of boys
g = number of girls
The ratio of the number of boys to the number of girls in a class is 5:4 means:
b / g = 5 / 4
Cross multiply
4 b = 5 g
Divide both sides by 5
4 / 5 b = g
g = 4 / 5 b = 0.8 b = 0.8 ∙ 15 = 12
Check results:
b / g = 15 / 12 = 3 ∙ 5 / 3 ∙ 4 = 5 / 4
Answer is 12
To find the number of girls in the class, we can use the given ratio of boys to girls, which is 5:4.
1. Divide the total number of boys by the ratio of boys to girls:
Number of girls = (Number of boys) * (Ratio of girls to boys)
= 15 * (4/5)
2. Calculate the number of girls:
Number of girls = 15 * 4/5
= 60/5
= 12
Therefore, there are 12 girls in the class.
To find the number of girls in the class, we can use the ratio given and the number of boys provided.
The ratio of boys to girls is given as 5:4, which means that for every 5 boys, there are 4 girls. Thus, we can set up a proportion:
Boys / Girls = 5 / 4
Substituting the given value of boys (15) into the proportion:
15 / Girls = 5 / 4
To solve for Girls, we can cross-multiply:
15 * 4 = 5 * Girls
60 = 5 * Girls
Dividing both sides of the equation by 5:
60 / 5 = Girls
12 = Girls
Therefore, there are 12 girls in the class.