I’m rly confused pls help

Weekly wages at a certain factory are normally distributed with a mean of $400 and a standard deviation of $50. find the probability that a worker selected at random makes between $450 and $500

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?

Billie holiday sells children's clothing for sara vaughn's toddler shop. baby blankets sell for $29.99 after a markup rate based on cost of 109%. find the cost and the markup.