Fiona wants to buy burgers from a restaurant which has the promotion below: 3 burgers for \( \$ 10 \) Buy 6 and get another 1 for free! To get 210 burgers, how much does she have to pay?

To determine how much Fiona needs to pay for 210 burgers under the given promotion, let's break down the offer and calculate the total cost step by step. ### **Promotion Details:** 1. **3 Burgers for \$10:** This means each set of 3 burgers costs \$10. 2. **Buy 6 and Get 1 Free:** Purchasing 6 burgers entitles Fiona to 1 additional burger for free. ### **Understanding the Combined Promotion:** - **Buying 6 Burgers:** Using the "3 for \$10" deal twice: \[ 2 \times 3 \text{ burgers} = 6 \text{ burgers} \quad \text{for} \quad 2 \times \$10 = \$20 \] - **Getting 1 Free Burger:** For every 6 burgers purchased for \$20, Fiona gets an additional burger for free. - **Total for 7 Burgers:** \[ 7 \text{ burgers} = 6 \text{ bought} + 1 \text{ free} \quad \text{for} \quad \$20 \] ### **Calculating the Total Cost for 210 Burgers:** 1. **Determine the Number of 7-Burger Sets in 210 Burgers:** \[ \frac{210 \text{ burgers}}{7 \text{ burgers per set}} = 30 \text{ sets} \] 2. **Calculate the Total Cost:** \[ 30 \text{ sets} \times \$20 \text{ per set} = \$600 \] ### **Conclusion:** Fiona needs to pay **\$600** to purchase 210 burgers under the given promotion. **Answer:** Fiona needs to pay $600 to purchase 210 burgers under the promotion.