Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
Carla's order at Mcdonald's costs $7.50, but she has a coupon for $2.50. If she gets an additional 20% discount for being a senior citizen, how much does she pay for her order in dollars total?

### Response:
First subtract the coupon amount from the price of the food: $7.50 - $2.50 = $<<7.5-2.5=5>>5.00
Then subtract 20% from 100% to find out what percentage of the reduced price Carla pays: 100% - 20% = 80%
Now multiply $5.00 by 80% to find out how much Carla pays: $5.00 * .8 = $<<5*.8=4.00>>4.00
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