SOLUTION: Lead Sample on a Farm Samples, Lead (ppm) 1,1523 2,847 3,1267 4,692 5,1401 6,1088 7,? To determine whether to buy a plot of land, a farmer is having the soil tested for

Question 1195125: Lead Sample on a Farm
Samples, Lead (ppm)
1,1523
2,847
3,1267
4,692
5,1401
6,1088
7,?
To determine whether to buy a plot of land, a farmer is having the soil tested for lead. The table above shows the amount of lead, in parts per million (ppm), in six of the seven samples of soil selected at random. If the average (arithmetic mean) amount of lead in the seven samples, in ppm, is no more than 1200, the farmer will buy the plot of land; otherwise, the farmer will not buy it. What is the greatest possible amount of lead, in ppm, that can be in the seventh sample if the farmer buys the land?

Answer by Shin123(626) (Show Source): You can put this solution on YOUR website!
The current sum of the lead samples is .
Let the amount of lead in the seventh sample be . Then, the average is . Multiplying both sides by 7, we get . Subtracting 6,188 from both sides, we get .
Therefore, the seventh sample must have 2,212 ppm or less of lead for the farmer to buy the land.
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