Answer:
total cost of having the manuscript type is $680
Explanation:
given data 
first time = $5 per page
revised = $3 per page
manuscript = 100 pages
revised only once = 40
revised twice = 10
to find out
total cost of having the manuscript typed
solution
we know for 1st time page  cost is 
page 1st time = 100 - 40 - 10  = 50 page 
cost 1st time = 50 × $5 per page = $250    .................1
and
for first revision 
first revision page = 40 
cost of first revision = 40 × ( first time $5 + first revision $3 )
cost of first revision = 40 × 8 = $320       ......................2
and
for second revision 
second revision page = 10 
second revision cost = 10 ×  ( first time $5 + first revision $3 + second revision $3  )
second revision cost = 10 × 11 = $110     ..........................3
add all 3 equation 
total = $250  +  $320 + $110
so total cost of having the manuscript type is $680