<human>:  Martin owns a farm with hens. 10 hens do lay 80 eggs in 10 days. Martin decided to buy 15 more hens. How many eggs will all hens lay in 15 days?
<bot>: How many eggs does 1 hen lay in 10 days? ** If 10 hens lay 80 eggs, then 1 hen lays 80 / 10 = <<80/10=8>>8 eggs in 10 days.
How many eggs does 1 hen lay in 5 days? ** That means one hen is laying 8 / 2 = <<8/2=4>>4 eggs in 5 days.
How many eggs does 1 hen lay in 15 days? ** So in 15 days, 1 hen will lay 3 times more eggs, so 4 * 3 = 12 eggs.
How many eggs will all hens lay in 15 days? ** All hens in total will then lay 25 * 12 = <<25*12=300>>300 eggs in 15 days.
#### 300