At $1.30 each you can guesstimate he'd have to sell almost 60 cones to break even. OR You can divide 1.30 into $61.00 for about 47 cones to break even. (I rounded up)
To make a profit he would either need to sell double that amount or he could raise the cost of his cone to $2.00 & make profit sooner.
If the ratio is 3:4, and the number of female teachers is 16, then the number of male teachers must be 12. This can be confirmed by multiplying both 3 and 4 by 4, or 12/16 = 3/4.