Question 305462
A company specializing in magazine sales over the telephone found that in 2500 phone calls,
 360 resulted in sales and were made by male callers, and 480 resulted in sales and were made by female callers.
 If the company gets twice as many sales per call with a woman's voice than with a man's voice,
 then how many of the 2500 calls were made by females?
:
Let x = no. of girls' call;
> Then (2500-x) = no. of boys' calls
> :
> We can say that percentage of successful calls (sales made) by
> girls is twice  the percentage made by boys
> :    
>   {{{480/x}}} = % made by girls
:    
>  {{{360/((2500-x))}}} = % made by boys
>  
> :
>  Girls % = 2 times boys
{{{480/x}}} = 2({{{360/((2500-x))}}})
:
{{{480/x}}} = ({{{720/((2500-x))}}})

> Cross multiply
> 720x = 480(2500-x)
>
> 720x = 1200000 - 480x
>
> 720x + 480x = 1200000
>
> 1200x = 1200000
>
> x = 1200000/1200
>
> x = 1000 calls made by girls
> :
> Check using percentage:
> 480/1000 = 48 %
> 360/1500 = 24 %