Three young women worked hard to earn money yo start a business. Their goal was to raise a total of 2100. Each day, girl A earned about 6.50, girl B raised three times as much as girl A, and girl C raised half as much as girl B.

Let's break down the amount each girl earned in a week:

Girl A earned 6.50 per day, so in a week (5 days), she earned 6.50 * 5 = 32.50.

Girl B earned three times as much as girl A, so she earned 3 * 6.50 = 19.50 per day. In a week, she earned 19.50 * 5 = 97.50.

Girl C earned half as much as girl B, so she earned 97.50 / 2 = 48.75 per day. In a week, she earned 48.75 * 5 = 243.75.

Adding up the amounts earned by each girl in a week: 32.50 (Girl A) + 97.50 (Girl B) + 243.75 (Girl C) = 373.75.

To reach their goal of 2100, the girls would need to work for 2100 / 373.75 ≈ 5.62 weeks.

Therefore, it would take the girls about 6 weeks to reach their goal of 2100.