i need some help with these two quadratic problems:

- A family drives 240 km to their cottage. They can save fuel by reducing their average speed by 20 km/h and this will mean that the trip will take one hour longer. What is this lower average speed?

- JB bought some balls for $600. If the cost for each ball had been 25 cents less, she would have had 10 more balls for her $600. How much did she pay for each ball.

can you help me set up the equation?

thank you for your expertise