35 binders can bind 1400 books in 21 days. How many binders will be required to bind 1600 books in 20 days?
Choose the correct option:
A) 87 B) 18 C) 42 D) 16 E) 10

Rationale: "binders books days 35 1400 21 x 1600 20 x / 35 = ( 1600 / 1400 ) * ( 21 / 20 ) = > x = 42 answer : c"
Answer: C