word problem

[sud21]

Which is more economic, copying or buying a $12.5 book with K pages?
1). K> 85
2). Copying a book with K+15 pages will cost more than $14

[neelgandham]

Which is more economic, copying or buying a $12.5 book with K pages?

1). K> 85

Not sufficient as it doesn't speak of monies

2). Copying a book with K+15 pages will cost more than $14

Cost for copying one page = 14/K+15
Cost for copying K pages = K*14/K+15
K*14/K+15 > 12.5 (For buying to be economical)
14k > 12.5K + 187.5
1.5K > 187.5
K > 125
So, if K > 125, then buying a K paged book is economical and if K < 125, then copying a K pages book is economical.
Not sufficient to answer.

From 1 and 2

K > 85, If K = 90 then copying a K pages book is economical and If K = 130 then buying a K paged book is economical. Insufficient to answer the question.

IMO E