Question in the image, please help

Blank × 10-3 is 2,000 times greater than 1.9 × 10-6. it is also blank times greater than 9.5 × 10-4.

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?

The ideal weight of a nickel is 0.176 ounce. to check that there are 40 nickels in a roll, a bank weighs the roll and allows for an error of 0.015 ounce in total weight