Answer :
Given:
Violinists : Cellists = 7:3.
Number of violinists in the school orchestra = 21
To find:
The combined number of cellists and violinists.
Solution:
Let the number of violinists and cellists in the school orchestra are 7x and 3x respectively.
Then, combined number of cellists and violinists is
[tex]\text{Combined number of cellists and violinists}=7x+3x[/tex]
[tex]\text{Combined number of cellists and violinists}=10x[/tex] ...(i)
Number of violinists in the school orchestra = 21
[tex]7x=21[/tex]
Divide both sides by 7.
[tex]x=3[/tex]
Now, the combined number of cellists and violinists is
[tex]\text{Combined number of cellists and violinists}=10(3)[/tex] [Using (i)]
[tex]\text{Combined number of cellists and violinists}=30[/tex]
Therefore, the combined number of cellists and violinists is 30.