To mail 10 letters costs $ 4.50 . How much would it cost for 12 letters? Assume the relationship is proportional.

12 letters cost 6.30 dollars

Step-by-step explanation:

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$5.40 for 12 letters

Step-by-step explanation:

you need to find the cost for 1 unit then multiply that by 12, so you take the cost (4.50) and divide it by letters (10) so you get 0.45. So that is the cost of q letter, then you that that unit rate and multi[ly it by the number that you need to figure out (12) so .45x12=5.40  

12 letters=$5.40

hi,

i'm 75% sure the answer is 1,1 to both lines.

have a great day

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step-by-step explanation: