Question 1198177


Let the fraction of those who had both be {{{x}}}.

Then 

{{{5/8 + 1/2+ 1/8 - x = 1}}}..........(Since there are only {{{4 }}}possible outcomes viz. Only measles, only chicken pox, neither and both)

Now solve for {{{x}}};...........Add all like terms on LHS 

{{{5/8 + 4/8+ 1/8 - x = 1}}}

{{{ 10/8 - x = 1}}}

{{{5/4 - x = 1}}}

{{{x= 5/4 - 1}}}

{{{x = 1/4}}}

Therefore, the fraction of those who had both diseases is {{{1/4}}}.