Please explain me this I WILL GIVE THE BRAINLIEST

Which expression is equivalent to 8(k + m) − 15(2k + 5m)?

8000 + 8800 + 8000 + 8 million + 80 trillion + another a katrillion equals

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