Answer:
First day - 25 calls
Second day - 16 calls
Third day - 75 calls
Explanation:
You need to set variables and create system of equations first.
First evening= x
Second evening= y
Third evening = z
x+y+z=116
z=3x
y=x-9
Now you plug in the values into the equation x+y+z=116
x+(x-9)+(3x)=116
5x-9=116
5x=125
x=25
You plug in the value of x into the other equations.
x= 25
z= 3*(25)=75
y=(25-9)=16
Rearrange so it corresponds with days...
First day - 25 calls
Second day - 16 calls
Third day - 75 calls