can someone help me?

Question

Joan works on commission for a furniture store. She gets a base pay of $80 a day plus 5 percent of the value of any merchandise she sells that exceeds a total of $400. Joan wrote the expression 400 + 0.05(t − 80), where t represents her sales total in dollars, to compute the total amount of money that she will make. For sales of $475 Joan calculated that she will make $419.75. Explain Joan’s error.

Answer 1

P = (base pay) + (commission)

 

base pay = $80

 

commission = 5% of sales above $400

 

t = total sales

 

commission = 0.05(t - $400)

 

Put it all together and get

 

P = $80 + 0.05(t - $400)

 

However, I assume there is no negative commission.  If sales are below $400, Joan would just get the base pay of $80, with no commission, never a negative commission.  So we should add that condition and modify the final answer to get

 

P = $80 + 0.05(t - $400) if t > $400 

P = $80 if t ≤ $400

 

 

Answer 2

p = $80 + 0.05(t - 400)