If a number in scientific notation takes the form of ax10^b, why does a have to be between 1 and 10

Olga bought a new skirt that cost $20. sales tax is 5%. how much did olga pay, including sales tax? 7.

What is the ratio for the surface areas of the cones shown below, given that they are similar and that the ratio of their radii and altitudes is 2: 1? submit

At a local museum, the total price for one adult and one child is $11. mrs. smith paid for herself and her three children. she spent $19. record the system of equations to be solved and then find the price of an adult and child ticket using either elimination or substitution.