Question 160771
 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 %
>
> Did this make sense to you?