d.s ratios and sufficiency

[missrochelle]

From GMAT Prep: Data sufficiency

Linda, Robert, and Pat packed a certain number of boxes with books. What is the ratio of the number of boxes of books that Robert packed to the number of boxes of books that Pat packed?

1. Linda packed 30 percent of the total number of boxes of books
2. Robert packed 10 more boxes of books than Pat did.

I know the answer on this problem has been discussed....My question is --- generally, is an equation involving a sum - in this case
"R = 10+P" ever sufficient to provide a ratio? I just dont see how it could ever hold if you're adding and the numbers can be any combination.

The only exception I can think of is whole integer constraints, where you are given a value and asked to find the qty's of something that must be positive integer.

any thoughts?

[Rahul@gurome]

In this case, it is certainly not sufficient. Here we have 4 unknowns and only 3 relations, so definitely in such types of cases it is not sufficient.

[pradeepkaushal9518]

ya rahul its like 3 unknown variable and 2 equations are given so never suff.