Question 1195125
The current sum of the lead samples is {{{1523+847+1267+692+1401+1088=6188}}}.
Let the amount of lead in the seventh sample be {{{x}}}. Then, the average is {{{(6188+x)/7<=1200}}}. Multiplying both sides by 7, we get {{{x+6188<=1200*7=8400}}}. Subtracting 6,188 from both sides, we get {{{x<=8400-6188=2212}}}.
Therefore, the seventh sample must have 2,212 ppm or less of lead for the farmer to buy the land.