[Question]: Ken had fifty pencils, and he wanted to share some of them with his two friends, Manny and Nilo. Ken gave ten pencils to Manny and ten more pencils to Nilo than he gave to Manny. He kept the rest of the pencils. How many pencils did Ken keep?
[Answer]: Nilo received 10 + 10 = 20. Thus, Ken gave a total of 10 + 20 = 30. Therefore, Ken kept 50 - 30 = 20 pencils.
So the answer is 20.

[Question]: 24 gallons per second of water flows down a waterfall. If you have an empty basin that can hold 260 gallons of water. The basin leaks water at 4 gallons per second. how long would it take to fill the basin with water from the waterfall in seconds?
[Answer]: 24 gallons in minus 4 gallons out is 24 - 4 = 20 gallons per second. 260 gallons divided by 20 gallons per second 260 / 20 = 13 seconds.
So the answer is 13.

[Question]: Sam bought a heavy safe with a combination lock. There were four rows with twenty gold bars per row arranged in the safe. If each gold bar is worth $20000, calculate the total worth of the gold bars in the safe.
[Answer]:
If there were four rows of twenty gold bars arranged in the safe, the total number of bars in the safe is 4 * 20 = 80 bars. Since each gold bar is worth $20000, the 80 bars are worth 80 * $20000 = $1,600,000.
So the answer is 1600000.