The ratio of boys to girls in a graduation class is 5:4. If there are 153 pupils in this class, how many boys are there?
5/9 = x/180
9x = 900
x = 100
Aaarrgghh! My demon dead brain cell pulled up 180 out of nowhere. (shaking head!)
Thanks for rescuing us, Reiny!
boys : girls = 5 : 4 or 5x : 4x
then 5x + 4x = 153
9x = 153
x = 17
5x = 85
4x = 68
there are 85 boys in the class
check:
85+68 = 153 , check!
85 : 68
= 5 : 4, check
To find the number of boys in the graduation class, we need to determine the value of the ratio.
The ratio of boys to girls is given as 5:4. This means that the total number of parts in the ratio is 5 + 4 = 9.
To find the number of boys, we can divide the total number of pupils by the total number of parts in the ratio, and then multiply that by the number of parts representing boys.
The total number of pupils in the class is given as 153. So, we set up the equation:
Number of boys = (Total number of pupils / Total number of parts) * Number of parts representing boys
Number of boys = (153 / 9) * 5
Simplifying, we get:
Number of boys = 17 * 5
Number of boys = 85
Therefore, there are 85 boys in the graduation class.