Pharmacy Tech Homework, i just need help if my answers are right.?

1. You dilute 100ml of a 75% solution with 300ml of water.What is the % strength of the diluted solution? my answer 18.75%??? 2.)You have 250ml of a 10% solution. You add 150ml of water. What is the final % strength of the solution? my answer : 6.25% ??? 3.) 50ml of a 2% is diluted to 125ml. What is the % strength of the diluted solution? 0.8%??? 4. If you add 175ml to 500ml of a 25% solution, what is the % strength of the diluted solution? my answer 8.75% Thanks