Statement: Your question is well elaborate and has all needed data.
Answer:
The surface area that will be painted is 376 ft2.
(18 neclaces)/(12 days) = 1.5 necklaces/day
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Rate is generally expressed in terms of quantity per time period. ("Per" means "divided by" here.) So, to find the rate, you divide the quantity by the corresponding time period, as above. There are other sorts of rates, but this is perhaps the most common.
You would have to add 47.50 + 122 to get 169.5 dollars. to get the amount of money he made in the summer, you would have to multiply 169.5 by 2 which would equal 339 dollars. so he made 339 dollars over the summer :)
