## Prealgebra (7th Edition)

$\frac{11}{25}$
The table shows 37 with the O+ blood type and 7 with the O- blood type, so 44 ($37+7$) have type O. The whole set of blood donors contained 100. $\frac{44}{100}=\frac{44\div4}{100\div4}=\frac{11}{25}$