The ratio of the price of a plane ticket for a child to the price of a plane ticket for an adult is 3:7. If Tina buys a child’s ticket and an adult’s ticket, she needs to pay 700 dollars. If Tina buys 5 adults’ tickets, how many dollars should she pay?

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Set the price of a child’s ticket as 3 units and the price of an adult ticket as 7 units. So the price sum is (3 + 7 = 10) units. Then,

10 units = $700.00

1 unit = 700 ÷ 10 = $70.00

7 units = 7 × 70 = $490.00

The price of an adult ticket is 490 dollars.

Thus, the cost for 5 adult tickets:

490 × 5 = $2450.00