Blood banks will shortly start to screen all donors for NANB hepatitis. Although the new screening tests are estimated to disqualify up to 5 percent of all prospective blood donors, they will still miss two-thirds of donors carrying NANB hepatitis. Therefore, about 10 percent of actual donors will still supply NANB-contaminated blood.

1. The argument above depends on which of the following assumptions?

(A) Donors carrying NANB hepatitis do not, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed.
(B) Donors carrying NANB hepatitis do not, in a large percentage of cases, develop the disease themselves at any point.
(C) The estimate of the number of donors who would be disqualified by tests for NANB hepatitis is an underestimate.
(D) The incidence of NANB hepatitis is lower among the potential blood donors than it is in the population at large.
(E) The donors who will still supply NANB-contaminated blood will donate blood at the average frequency for all donors.

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2. Which of the following inferences about the conse-quences of instituting the new tests is best supported by the passage above?

(A) The incidence of new cases of NANB hepatitis is likely to go up by 10 percent.
(B) Donations made by patients specifically for their own use are likely to become less frequent.
(C) The demand for blood from blood banks is likely to fluctuate more strongly.
(D) The blood supplies available from blood banks are likely to go down.
(E) The number of prospective first-time donors is likely to go up by 5 percent.

It is a tough one...

My guess is (E) and (A).


1. (E)

The author specifies a number - 10%. If the donors with NANB-contaminated blood donate blood more frequently, it won't be 10% any more. Therore, the average frequency has to remain unchanged.

2. (A)

It is (A) because the article is talking about NANB incidence...

E and D

but looking at your answers guys and I feel that the second one should be A. Nevermind, I keep my original choice

I'll go with gamjatang on this one too, but these questions have me in tangles.

A and D.

In 1. E is wrong, the argument states what percentage of donors have the disease, regardless of how often they donate. E is irrelevant.
D is wrong, we do not know wether donors are the only persons infected by the disease, we cannot tell wether D is right.
A is right because if there are 15% donors infected, 5% are ruled out by the new test and still 10% are doning, it means that none of them has been ruled out by any other cause.

I go for 1.A and 2.D.

My reasons are same as ranga41's.

BTW, what's the OA?

I don't agree with the second one.

IF 10% of the blood donars supply NANB contaminated blood , the number of new incidence is not necessary increase by 10%........

Suppose in a population there are 100 NANB contaminated people every year.
Out of that X went for blood donation.....two third of them gave the blood so it means the new incidence will be increased by two third X....how it can be 10%...it can be any.....

Pleqase if anyone can explain.....

source of these questions is "GMAT语法"

Now, not sure what this means.....probably, from some chinese site

wud be great if some one finds out what this is??

Even I'm not sure if the answers they gave are authentic..moveover, none of them have explanations...

KRishna

Hi Guys,

sorry guys,
Seems like the answers with me are wrong ( I always suspected thier correctness)

gotoknow3, thanks for the update...

Thanks,
KRishna