A university professor fails 20% of his students in the final. After the final, he polls the students and asks how many of them studied more than 3 hours for it. Of those who passed the final, 72% said that they
studied for it. Of those who failed the final, 31% said they studied for it. Make a tree diagram for this
problem and then answer the following questions.

Use multiples to write two fractions equivalent to 7/9. 14/18, 8/10 6/8, 21/27 10/12, 28/36 14/18, 21/27

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.

Atriangle has side lengths of x, x+11, and 3x+5. what is the perimeter? question 1 options: 3x2+38x+55 3x3+38x2+55x 5x+16 4x+16