Of the 70 children who visited a certain doctor last week,

Question

Of the 70 children who visited a certain doctor last week, how many had neither a cold nor a cough?

(1) 40 of the 70 children had a cold but not a cough.

(2) 20 of the 70 children had both a cold and a cough.

Bunuel · Answer

All={Children with a cough ONLY}+{Children with a cold ONLY}+{Children with a cough AND a cold}+{Children with neither a cold nor a cough} --> 70={Children with a cough ONLY}+{Children with a cold ONLY}+{Children with a cough AND a cold}+{Children with neither a cold nor a cough}

(1) 40 of the 70 children had a cold but not a cough --> so {Children with a cold ONLY}=40. Not sufficient.

(2) 20 of the 70 children had both a cold and a cough --> so {Children with a cough AND a cold}=20. Not sufficient.

(1)+(2) 70={Children with a cough ONLY}+40+20+{Children with neither a cold nor a cough} --> 10={Children with a cough ONLY}+{Children with neither a cold nor a cough}, still 2 unknowns. Not sufficient.

Answer: E.

pradeepskunwar · Answer

great explanation bunuel. thanks!

aim730 · Answer

Answer E

To calculate the result one should the nos of Children who had Cough but not cold.

aiming4mba · Answer

Bunuel, you're the best!

oldstudent · Answer

Bunuel is the reason for the success of this forum. Thanks a lot to Bunuel!!

bumpbot · Answer

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Of the 70 children who visited a certain doctor last week,

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