Solve these coin problems:
1) james bought 80 postage stamps for which he paid $18.40. some were 1 cent stamps and some were 33 cent stamps. how many of each kind did he buy?
2) a postal clerk sold 75 stamps for $19.90. some were 20 cent and some were 34 cent stamps. how many of each kind did he sell?

Anyone know these questions? i need ,.

As a salesperson you get $50/day and $3.60/each sales you make.if you want to make $60 in one day, how many sales would you need need to make ? a 3b 4c 5d 6 show work.

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