In Exercises 3-6, use the figure. i need help with all of them

i don’t understand this assignment that my teacher assigned to me. please help me.

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.

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

Sara made $253 for 11 hours of work. at the same rate how much would he make for 7 hours of work?