<human>:  Jacob can write twice as fast as Nathan. Nathan wrote 25 letters in one hour. How many letters can the two write in 10 hours together?
<bot>: How many letters does Jacob write in an hour? ** Since Nathan writes 25 letters in an hour, Jacob writes 25*2 = <<25*2=50>>50 letters in an hour.
How many letters do the two write in an hour together? ** Together, they write 50+25 = <<50+25=75>>75 letters in an hour,
How many letters will the two write in 10 hours together? ** In 10 hours, they'll write a total of 75*10 = <<10*75=750>>750 letters
#### 750