Patty needs a total of 80 to buy a bicycle. She has already saved 35. If she saves 10 a week from her earnings what is the least number of weeks she must work to have enough money to buy the bicycle?

Patty needs a total of 80 and has already saved 35, so she needs an additional 80 - 35 = 45. If she saves 10 a week, the least number of weeks she must work is 45 ÷ 10 = 4.5. Since she cannot work a fraction of a week, she needs to work at least 5 weeks to have enough money.