Suppose the fraction of sales for male callers is k, then the fraction for

femail callers is 2k.

If there were m callers with male voices and f callers with femail voices, then:

km=360,

and:

2kf=480.

Also:

m+f=2500 (or 3500, you will have to sort out which this is yourself),

so:

km+kf=360+240=k 2500.

so:

k=600/2500=0.24, and

so:

2x0.24xf=480,

which gives:

f=1000.

RonL