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A hardware store receives bolts from two suppliers. A bolt is selected
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05 Aug 2026, 03:18
05 Aug 2026, 03:18
Expert Reply
00:00
Question Stats:
33% (01:07) correct
66% (03:37) wrong based on 3 sessions
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A hardware store receives bolts from two suppliers. A bolt is selected by first randomly choosing one of the two suppliers, Supplier A or Supplier B, each with probability \(\frac{1}{2}\) , and then selecting one bolt at random from that supplier's full shipment.
Supplier A's shipment contains 40 bolts, of which 10 are galvanized. Among the galvanized bolts, 4 do not come with a washer.
Supplier B's shipment contains 20 bolts, of which 15 are galvanized. Among the galvanized bolts, 3 do not come with a washer.
Given that the selected bolt is galvanized and does not come with a washer, what is the probability that it came from Supplier B?
(A) \(\frac{1}{5}\)
(B) \(\frac{2}{5}\)
(C) \(\frac{3}{7} \)
(D) \(\frac{3}{5}\)
(E) \(\frac{4}{7} \)
Supplier A's shipment contains 40 bolts, of which 10 are galvanized. Among the galvanized bolts, 4 do not come with a washer.
Supplier B's shipment contains 20 bolts, of which 15 are galvanized. Among the galvanized bolts, 3 do not come with a washer.
Given that the selected bolt is galvanized and does not come with a washer, what is the probability that it came from Supplier B?
(A) \(\frac{1}{5}\)
(B) \(\frac{2}{5}\)
(C) \(\frac{3}{7} \)
(D) \(\frac{3}{5}\)
(E) \(\frac{4}{7} \)
- Part of the project: GRE Daily Quant Challenge ALL 4 CORE QUANT AREAS
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A hardware store receives bolts from two suppliers. A bolt is selected
[#permalink]
07 Aug 2026, 11:48
07 Aug 2026, 11:48
1
Expert Reply
Solution
Since each supplier is chosen with equal probability, just compare the chances of getting a galvanized bolt with no washer from each supplier.
Supplier A: \(\frac{4}{40}=\frac{1}{10}\)
Supplier B: \(\frac{3}{20}\)
So,
P(B∣galvanized, no washer)= (3/20)/[(1/10)+(3/20)] =3/5
Answer: D
Since each supplier is chosen with equal probability, just compare the chances of getting a galvanized bolt with no washer from each supplier.
Supplier A: \(\frac{4}{40}=\frac{1}{10}\)
Supplier B: \(\frac{3}{20}\)
So,
P(B∣galvanized, no washer)= (3/20)/[(1/10)+(3/20)] =3/5
Answer: D
gmatclubot
A hardware store receives bolts from two suppliers. A bolt is selected [#permalink]
07 Aug 2026, 11:48
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