Final answer:
Carlos has spent between $7 and $10 on music downloads this month since he is allowed a $10 allowance and has spent within $3 of this allowance.
Step-by-step explanation:
Carlos is allowed to download a total of $10 worth of music each month. He has spent within $3 of his allowance. To find the range of money he could have spent, we take his allowance and create two scenarios. In the first scenario, Carlos spends $3 less than his allowance, which would be $10 - $3 = $7. In the second scenario, he spends his full allowance, which would be $10. Therefore, the range of money Carlos has spent on music downloads this month is between $7 and $10.