Proper order from least to greatest 2/3,7/6,1/8,9/10

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?

Alicia puts $400 in a bank account. each year the account earns 5% simple interest. how much money will be in her bank account in six months?

3x = 729 solve for x plz . it's urgent. will mark