i need help on my math hw?

Billy L asked:


how do u do these questions.. can you show work if possible.. thx =D

1. Sarah can eat a box of popcorn in 10 minutes. Janet can eat a box of popcorn in 15 minutes. They go to the movies and share a box of popcorn. How long will it take them to finish it?

4. A car leaves Elk Grove to L.A. at 55 mph. an hour later a second car leaves EG to L.A traveling at 75 mph. How long will it be before the second car catches the first car?

5. Mr. Reed has a 40% solution of plant food and a 10% solution of plant food. He wants to make 10 liters of a 20% food plant mixture. How many liters of each kind does he need?

thx..

BEAIRD