The ratio of boys to girls at KJH is 4 to 5. How many girls would there be if there was a total of 360 students?

Answer 1

so the population of this student body is divided

into 4+5=9 equal parts, 4 of which are boys and

5 are girls

boys:

(4/9)*360 = 4/9 * 360/1 = 4/1 * 40/1 <--- 360 cancels 9 by factor of 40

= 160 boys

girls:

(5/9)*360 = 5/9 * 360/1 = 5/1*40/1 <--- 360 cancels 8 by factor of 40

= 200 girls

160+200 = 360

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Another way to do it is like this...

Let x be the amount in each of the 9 equal parts...

4x + 5x = 360

9x = 360

x=40

boys are 4x = 4(40) = 160

girls are 5x = 5(40) = 200