SOLUTION: Half the sum of the atomic number of two elements is 75. The first element is 8 less than twice the second element. What are the two elements and their atomic number?

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Question 1008034: Half the sum of the atomic number of two elements is 75. The first element is 8 less than twice the second element. What are the two elements and their atomic number?

Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
Call their atomic numbers x and y. We have
(1/2)(x + y) = 75 or x + y = 150
x = y - 8 or x - y = -8
Add these together and get
2x = 142
x = 71 ==>Lutetium
y = 79 ==>Gold