SOLUTION: The ratio of girls to boys in a class was 4:5. after 4 girls were added to the class, it was found that the number of boys and girls was now equal. how many students are now in t

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: The ratio of girls to boys in a class was 4:5. after 4 girls were added to the class, it was found that the number of boys and girls was now equal. how many students are now in t      Log On


   

Question 315475: The ratio of girls to boys in a class was 4:5. after 4 girls were added to the class, it was found that the number of boys and girls was now equal. how many students are now in the class ?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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The ratio of girls to boys in a class was 4:5.
after 4 girls were added to the class, it was found that the number of boys and girls was now equal.
how many students are now in the class ?
:
"The ratio of girls to boys in a class was 4:5."
g%2Fb = 4%2F5
Cross multiply
5g = 4b
:
" 4 girls were added to the class, it was found that the number of boys and girls was now equal."
b = g + 4
:
Replace b with (g+4) in the 1st equation
5g = 4(g+4)
5g - 4g = 16
g = 16 girls
then
b = g + 4
b = 16 + 4
b = 20 boys
:
" how many students are now in the class ?
After adding 4 girls, 20 + 20 = 40 students now