Explain why you would make one of the addends a ten number when solving a addition problem

What is the slope of the line shown below?

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!

An object in geometry with no width, length or height is a(n):