The pairs of polygons below are similar. Give the sale factor of figure A to figure B

Which values for a and b will create infinitely many solutions for this system of equations? ax-y=8 2x+y=b

Anyone know? will mark brainliest if correct

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?