Data Sufficiency

Could some one answer why the ans of attached question is E? I could find out the ratio using both statements.

1. First statement says that Linda Packed 30 % of books
2. 2ns statement says that robert packed 10 more books than pat.

as we need to find the ratio of robert/Pat
let's assume there are 100 books from first statement we know that Linda packed 30 of them so 70 books were packed by Robert and Pat.
Sec. statement says that robert packed 10 more books than Pat so the no. of books packed by robert must be 40 and linda must have packed 30 books.
This would give us the ratio of no of books packed by Robert and Pat - 40/30 = 4/3

Please correct me ?

In your process there is a small error.You have considered the total number of books as 100 which is not stated anywhere

Let us take total number of books be 100x

From 1
robert and pa togather packed 70x books...no infomation how many they packed individually...no sufficient

From 2
number of books of pat+10=number of books of robert...not sufficient

Combining
number of books of pat+number of books of robert=70x and
number of books of robert-number of books of pat=10

Number of books of Robert=35x+5
Number of books of Pat=35x-5
ratio 35x+5/35x-5=7x+1/7x-1...but unless we know x ratio cannot be calculated.....hence not sufficient

Ans option E


[spoiler][/spoiler]

hmboy17,

It's safe to plug in values instead of ratios/percentages as long as the question doesn't limit you to any concrete number. From the moment statement (2) gives us a concrete number (the difference between R & P is known as 10), it becomes unsafe to plug in values.

You can see a step by step video solution: this is GMATPrep question 1041

Best of luck,
-Patrick