Question 97648
An atom has a mass number of 108. The number of neutrons is 1.25times the number of protons. How many protons are in the nucleus if 
mass number= neutrons + protons?
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108 = 1.25x + x
108 = 2.25x
x =  48 (number of protons)
1.25x = 60 (number of neitrons)

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Cheers,
Stan H.