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A survey of 120 teachers determined the following:

70 had high blood pressure
40 had heart trouble
20 had both high blood pressure and heart trouble

What percent of the teachers surveyed had neither high blood pressure nor heart trouble?

 Jul 24, 2019
 #1
avatar+23180 
+3

A survey of 120 teachers determined the following:

70 had high blood pressure
40 had heart trouble
20 had both high blood pressure and heart trouble

What percent of the teachers surveyed had neither high blood pressure nor heart trouble?

 

Frist solution:

\(\begin{array}{|l|c|c|c|} \hline & \text{blood} & \overline{\text{blood}} \\ & \text{pressure} & \overline{\text{pressure}} \\ \hline \text{heart} & \mathbf{20} & 40-20=20 & \mathbf{40} \\ \text{trouble} & & & \\ \hline \overline{\text{heart}} & & \color{red}x =50-20 = \mathbf{30} \\ \overline{\text{trouble}} & \\ \hline & \mathbf{70} & 120-70=50 & \mathbf{120} \\ \hline \end{array}\)

 

Second solution:

\(\begin{array}{|l|c|c|c|} \hline & \text{blood} & \overline{\text{blood}} \\ & \text{pressure} & \overline{\text{pressure}} \\ \hline \text{heart} & \mathbf{20} & & \mathbf{40} \\ \text{trouble} & & & \\ \hline \overline{\text{heart}} & 70-20=50 & \color{red}x = 80-50 =30 & 120-40 = 80 \\ \overline{\text{trouble}} & \\ \hline & \mathbf{70} & & \mathbf{120} \\ \hline \end{array}\)

 

laugh

 Jul 24, 2019
 #2
avatar+1338 
0

Nice Heureka! You beat me to it though... :P

tommarvoloriddle  Jul 24, 2019
 #3
avatar+1338 
0

nvm. Sorry!

tommarvoloriddle  Jul 24, 2019
edited by tommarvoloriddle  Jul 24, 2019

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