Jonathan and Bill need to stack firewood. Jonathan can stack 130 pounds of firewood in 2 hours. Bill can stack 150 pounds of firewood in 3 hours. How long will it take them to stack 400 pounds of firewood if they work together (round to the nearest hundredth)?

J can stack 400 lbs in 2*400/130 = 6.15 hrs

B can stack 400 lbs in 3*400/150 = 8 hrs

1/X = 1/6.15 + 1/8
X = 3.48

5.71 hours

To find out how long it will take Jonathan and Bill to stack 400 pounds of firewood together, we need to determine their combined rate of work.

First, let's find Jonathan's rate of work. We know that Jonathan can stack 130 pounds of firewood in 2 hours. So his rate of work is 130 pounds divided by 2 hours, which gives us 65 pounds per hour.

Next, let's find Bill's rate of work. We know that Bill can stack 150 pounds of firewood in 3 hours. So his rate of work is 150 pounds divided by 3 hours, which gives us 50 pounds per hour.

Now, to find their combined rate of work, we add Jonathan and Bill's rates of work together. So their combined rate of work is 65 pounds per hour + 50 pounds per hour, which equals 115 pounds per hour.

Finally, to find the time it will take them to stack 400 pounds of firewood, we divide the total amount of firewood (400 pounds) by their combined rate of work (115 pounds per hour).

400 pounds ÷ 115 pounds per hour = 3.48 hours.

Therefore, it will take them approximately 3.48 hours, or rounded to the nearest hundredth, 3.48 hours, to stack 400 pounds of firewood if they work together.