AP EAMCET Engineering 2018 Apr 24 Shift 1 Paper

Let's assume that the number of protons in X is equal to ′a′
Thus, number of neutrons becomes 0.166a+a=1.166a
since,
Mass number = Number of protons + Number of neutron
52=a+1.166a
52=2.166a
a=24
'24' protons signify that the element X is 24Cr
Now, let's assume that the number of protons in Y is equal to ′b′.
Thus, number of neutrons becomes 0.273b+b=1.273b
since,
Mass number = Number of protons + Number of neutron
75=b+1.273b
75=2.273b
b=33
‘33’ protons signify that the element Y is 33As .