Can someone please help me?! ASAP

Bed a is seven feet long. bed b is 7/8 of bed a. bed c is 7/8 of bed b. bed d is 7/8 of c. a. come up with an expression for the length of bed d. b. what is the length of bed d?

One positive number is 9 more than twice another. if their product is 95, find the numbers

Researchers are conducting experiments to determine the role of alcohol in the development of depression. after the study is complete, they determine that the relative risk of developing depression is 1.55 with a 95 % ci of 1.2 -1.9. each group is then divided into nonsmokers and smokers. the relative risk for the nonsmokers is 1.12 with a 95% ci of 0.87-1.37. the relative risk for the smokers is 1.7 with a 95 % cl of 1.5-1.9. what type of bias may affect this study? a. procedure bias b. recall bias c. selection bias d. confounding e. lead-time bias