to the person who gets the correct answer: How can statement 1 not identify that the difference is less than 10 lbs if the max that each of the 10 pieces could be off was .9999999999?

the max possible rounding error =0.5 *18 =9 pounds

so the total error is definitely less than 10 pounds.

so (B) is sufficient to answer.

B

stmnt: all pieces <9.5 pds, if all are integers then he need to round up or down. we do not know the number of beef pieces. not suff

stmnt: 18 pcs of beef. what if all pcs had integer wghts. then there would be no diff b/w actual and recorded weight.
max difference between actual and recorded possible when all weights are 0.5 pds (anything less than 0.5 will be rounded down to 0, not possible) rounded to 1pd each, max difference=0.5*18=9<10 sufficient

4meonly wrote:OA B

IMO the answer shd be C

Reasoning

1) All the pieces weigh < 9.5
This does not say the count of pieces and for which we cannt calculate the total difference
for e.f if total number of pieces are 50 ,even a diff of 0.3 will give us final total diff as 15(50x.3) whereas if number of pieces are less say 10 total diff could be less than 10
hence in sufficient

2)Total 18 piece of beef were there
It doesnt says the margin of diff
hence insufienct

(1)+(2)
The maximum diff for any weigh which can be rounded is 0.5
(coz if value is say 8.6 it will be rounded to 9 as nearest integer hence diff is 0.4 ,but for 8.5 it gives 0.5 as diff)
hence (0.5 * 18) gives 9 which is less than 10
hence C is sufficent


Hence IMO :C