Telephone Cellular sells phones for $100. The unit variable cost per phone is $50 plus a selling commission of 10% (based on the unit sales price...

U.S. Telephone Cellular sells phones for $100. The unit variable cost per phone is $50 plus a selling commission of 10% (based on the unit sales price per phone). Fixed manufacturing costs total $1,220 per month, while fixed selling and administrative costs total $2,300. How many phones must be sold to achieve the breakeven point?