1992 AMC 12 Problem 2

Attempt Problem 2 of the 1992 AMC 12 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1992 AMC 12 solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

An urn is filled with coins and beads, all of which are either silver or gold. Twenty percent of the objects in the urn are beads. Forty percent of the coins in the urn are silver. What percent of the objects in the urn are gold coins?

40\%

48\%

52\%

60\%

80\%

Answer: B

Concepts:percent complementary percentage

Difficulty rating: 890

Small hint:

First find the percent of all objects that are coins

Big hint:

Of those coins, use the complement of the silver percentage

Solution:

Coins make up

80\%

of the objects, and

60\%

of the coins are gold. Thus gold coins make up

0.80\cdot0.60=0.48=48\%

of all the objects.

Thus the correct answer is B.