1+1+2+3+4+5+6+7+8+9=?

5500 dollars is placed in an account with an annual interest rate of 6.5%. to the nearest tenth of a year, how long will it take for the account value to reach 19700 dollars?

Me! 50 points! why does when we come home, our door is unlocked and there is grease on the door knob, me solve this , and i don't know what category this goes under

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?