Kali left school and traveled toward her friend’s house at an average speed of 40
km/h, matt left one hour later and traveled in the opposite direction with an average speed of 50 km/h. find the number of hours matt needs to travel before they are 400 km apart.

how can i figure out an equation to solve this problem?

Matt needs to travel 3 hours. 
If 40km=1 hour
   400km=? But there are two distances
200/40*1=5 hours
Therefore Kali needs to travel 5 hours to be 200 km away from the house.
If 50km=1 hour
200km=?
200/50*1hr=4hrs Therefore Matt needs to travel 4hrs to be 200 km away from the house. But Kali traveled 1hr earlier than Matt. 4hrs-1hr=3hrs
Therefore Matt has to travel for 3 hours to be 400km away from Kali.

Answer for 2: his profit would be $2.88 explanation: you have to first multiply 72 and 0.12 together to get $8.64 once you do that you know how much money the shopkeeper made from selling the candy bars individually. so you have to do 8.64-5.76=2.88 hope that ; )answer for 3: yeah i’m sorry i have no idea what number 3 is. i’m sorry i couldn’t with that.