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?
+26393 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:
\(\begin{array}{|l|c|c|c|} \hline & \text{blood} & \overline{\text{blood}} \\ & \text{pressure} & \overline{\text{pressure}} \\ \hline \text{heart} & \mathbf{20} & & \mathbf{40} \\ \text{trouble} & & & \\ \hline \overline{\text{heart}} & 70-20=50 & \color{red}x = 80-50 =30 & 120-40 = 80 \\ \overline{\text{trouble}} & \\ \hline & \mathbf{70} & & \mathbf{120} \\ \hline \end{array}\)
