Which biconditional is not a good definition?
a) a whole number is odd if and only if the number is not divisible by 2
b) an angle is straight if and only if it is measure is 180°
c) a whole numbers even if and only if it is divisible by two
d) a ray is a bisector of an angle if and only if it's blitz the angle into two angles

Asix-sided die of unknown bias is rolled 20 times, and the number 3 comes up 6 times. in the next three rounds (the die is rolled 20 times in each round), the number 3 comes up 6 times, 5 times, and 7 times. the experimental probability of rolling a 3 is 10 %, which is approximately % more than its theoretical probability. (round off your answers to the nearest integer.)