Which whole number is closest to √149

The table shows the distance traveled over time while traveling at a constant speed.

What is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?