A female dust mite is 0.42 millimeter long. How do u write this measurement in scientific notation

5,600 x 10^3 = a) 560 b) 5,000,600 c) 5,600,000 d) 56,000

Two cyclists 84 miles apart start riding toward each other at the same. one cycles 2 times as fast as the other. if they meet 4 hours later, what is the speed (in mi/h) of the faster cyclist?

Boris needs to buy plastic spoons. brand a has a box 42 spoons for $2.37. brand b has a box of 72 spoons for $3.57. find the unit price for each brand. then state which brand is the better buy based on the unit price. round your answer to the nearest cent.