Events & Promotions
|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Apr 2711:00 AM EDT
-12:00 PM EDT
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors
Apr 2808:00 AM PDT
-11:00 AM PDT
Whether you are just beginning your MBA journey or fine-tuning your path to a 700+ score, GMAT Day is designed to give you a competitive edge.
16 Sep 2014, 00:55
Kudos
Bookmarks
A right circular cylinder-shaped coin made of an aluminum-silver alloy weighs 30 grams and has a diameter of 15 mm and a height of 2 mm. The coin contains equal volumes of aluminum and silver, with silver being twice as heavy as aluminum. What is the weight of a pure aluminum circular cylinder-shaped coin with a diameter of 30 mm and a height of 1 mm? (The volume of a right circular cylinder is given by \(\pi*r^2*h\), where \(r\) is the radius of the base and \(h\) is the height of the cylinder.)
A. 36 grams
B. 40 grams
C. 42 grams
D. 48 grams
E. 80 grams
A. 36 grams
B. 40 grams
C. 42 grams
D. 48 grams
E. 80 grams
16 Sep 2014, 00:55
Kudos
Bookmarks
Official Solution:
A right circular cylinder-shaped coin made of an aluminum-silver alloy weighs 30 grams and has a diameter of 15 mm and a height of 2 mm. The coin contains equal volumes of aluminum and silver, with silver being twice as heavy as aluminum. What is the weight of a pure aluminum circular cylinder-shaped coin with a diameter of 30 mm and a height of 1 mm? (The volume of a right circular cylinder is given by \(\pi*r^2*h\), where \(r\) is the radius of the base and \(h\) is the height of the cylinder.)
A. 36 grams
B. 40 grams
C. 42 grams
D. 48 grams
E. 80 grams
Let \(s\) be the weight of silver and \(a\) be the weight of aluminum in the first coin. Since \(s + a = 30\), and silver is twice as heavy as aluminum, we can write \(2a + a = 30\), which simplifies to \(a=10\) grams. Therefore, the weight of the aluminum in the coin is 10 grams. If the coin were made of pure aluminum, then its weight would be 20 grams since it contains equal volumes of aluminum and silver.
The volume of the first coin is \(\pi*r^2*h = \pi*(\frac{15}{2})^2*2 =\pi*\frac{225}{2}\).
The volume of the second coin is \(\pi r^2 h = \pi*(\frac{30}{2})^2*1 =\pi*225\).
Since the first coin, if it were made of pure aluminum, would weigh 20 grams. we can conclude that the second coin, which is twice as large as the first, weighs 40 grams.
Answer: B
A right circular cylinder-shaped coin made of an aluminum-silver alloy weighs 30 grams and has a diameter of 15 mm and a height of 2 mm. The coin contains equal volumes of aluminum and silver, with silver being twice as heavy as aluminum. What is the weight of a pure aluminum circular cylinder-shaped coin with a diameter of 30 mm and a height of 1 mm? (The volume of a right circular cylinder is given by \(\pi*r^2*h\), where \(r\) is the radius of the base and \(h\) is the height of the cylinder.)
A. 36 grams
B. 40 grams
C. 42 grams
D. 48 grams
E. 80 grams
Let \(s\) be the weight of silver and \(a\) be the weight of aluminum in the first coin. Since \(s + a = 30\), and silver is twice as heavy as aluminum, we can write \(2a + a = 30\), which simplifies to \(a=10\) grams. Therefore, the weight of the aluminum in the coin is 10 grams. If the coin were made of pure aluminum, then its weight would be 20 grams since it contains equal volumes of aluminum and silver.
The volume of the first coin is \(\pi*r^2*h = \pi*(\frac{15}{2})^2*2 =\pi*\frac{225}{2}\).
The volume of the second coin is \(\pi r^2 h = \pi*(\frac{30}{2})^2*1 =\pi*225\).
Since the first coin, if it were made of pure aluminum, would weigh 20 grams. we can conclude that the second coin, which is twice as large as the first, weighs 40 grams.
Answer: B
General Discussion
23 Jul 2016, 23:54
Kudos
Bookmarks
I think this is a high-quality question and I agree with explanation.
