A group consisted of 2 girls for every boy. 24 more girls joined in the class. There are now 5 girls for every boy. How many are in the class?
Situation 1:
\(\frac{g}{b}=2\rightarrow g=2b\)
Situation 2:
\(\frac{g+24}{b}=5\\
\\
g+24=5b\)
Replacing g in the second equation:
\(2b+24=5b\\
\\
3b=24\\
\\
b=8\\
\\
g=2b\\
\\
g=16\)
In the Situation 1 there was 16 girls and 8 boys = 24 persons
In the Situation 2 there are 40 girs + 8 boys = 48 persons
\(in\ the\ class\ are\ n\ boys\ \ \ \Rightarrow\ \ 2n+24=5n\ \ \Rightarrow\ \ 3n=24\ \ \Rightarrow\ \ n=8\\\ =8\ \ \Rightarrow\ \ 5n=5\cdot 8=40\ (girls)\\\\40+8=48\\\\Ans.\ in\ the\ class\ are\ 48\ students.\)