12 people working together can count a box of votes in 4 hours. how long will it take 30 people to count 10 boxes of votes?

12 people can  count 1/4 box in  one hour

So 1 person  can count  1/ 4 * 1/12  =    1/48 box in  1 hr

So

30 people can count   30 * (1/48)  = 30/48 =  5/8  of a box in  1  hour

So

30  / (5/8) =   48 hrs