Subject: mathqa
Question: rates for having a manuscript typed at a certain typing service are $ 6 per page for the first time a page is typed and $ 4 per page each time a page is revised . if a certain manuscript has 100 pages , of which 40 were revised only once , 10 were revised twice , and the rest required no revisions , what was the total cost of having the manuscript typed ?
Option: 
A: $ 850
B: $ 860
C: $ 840
D: $ 880
Answer: C