Write the next number in this pattern. 10,11,20,21,30,31

Tim open up a new saving account with a $50 deposit and plant to deposit $20 per week into the same account.write an expression to represent the total amount in his savings account.

Ithink i know it but i want to be sure so can you me out ?

Sandy is upgrading her internet service. fast internet charges $20 for installation and $52.45 per month. quick internet has free installation but charges $57.45 per month. part 1 out of 2 complete the equation that can be used to find the number of months after which the internet service would cost the same. use the variable x to represent the number of months of internet service purchased.