Maths question, can't think today so need help(explain )?

Question

1) melissa works at an advertising agency. she recives $450 per week plus 3% commission on any advertising work she brings to the company. if mellissa bought $ 17000 work of advertising to the company in 1 week, calculate her gross income fo that week.

1) my answer is $1410

2) john erans a commission on his sales of fassion items. for goods to the value of $ 2000 he recives 6% and fo sales over $2000 her recives 9%. in a given week he sold $ 4750 worth of goods. find the comission earned.

3) greg earns $578 goss per week. if he wishes to pay 3% of his salary towards supeannuation, determine the amout of superannuatuion he will contribute

4) a real estate agent receives 2.75% comission on the sales of a house valued at $125000. find the commison earned.

Answer 1

1) 0.03(17000) + 450 = 510 + 450 = $960

2) 0.06(2000) + 0.09(4750 - 2000) = 120 + 247.50 = $367.50

3) 0.03(578) = $17.34

4) 0.0275(125000) = $3437.50