Answer:
Grade A 2:9
Grade B 1:3
Grade C 4:15
Step-by-step explanation:
Students in grade A:
[tex]450-(120+80)=450-200=250[/tex]
if the ratio is 2:3 then
[tex]A=(250/5)(2)=(50)(2)=100[/tex] students
The ratio of students with grade A:
[tex]\frac{100}{450}=\frac{10}{45} =\frac{2}{9}[/tex]
= [tex]2:9[/tex]
Students with grade B.
[tex]B=250-100=150[/tex]
The ratio of B:
[tex]\frac{150}{450} =\frac{15}{45} =\frac{1}{3}[/tex]
[tex]= 1:3[/tex]
Ratio of students with grade C:
[tex]=\frac{120}{450} =\frac{12}{45} =\frac{4}{15}[/tex]
[tex]=4:15[/tex]
Hope this helps
