Getting stuck on these problems

If the cost to mail a package is an initial $5 and $0.28 for every pound the total cost to mail a package was $11.27, how much did the package weigh?

Dakota earned $7.50 in interest in account a and $18.75 in interest in account b after 15 months. if the simple interest rate is 4% for account a and 5% for account b, which account has the greater principal? explain. to make it a little easier, there is an image. good luck!

Find the missing variable for a parallelogram: a = latex: 28in^2 28 i n 2 h = b = 6.3 in (1in=2.54cm)