Difference between revisions of "2019 AMC 10B Problems/Problem 7"
Sevenoptimus (talk | contribs) m (Removed irrelevant attribution) |
Ironicninja (talk | contribs) (Undo revision 103280 by Sevenoptimus (talk)) (Tag: Undo) |
||
Line 10: | Line 10: | ||
If he has enough money to buy <math>12</math> pieces of red candy, <math>14</math> pieces of green candy, and <math>15</math> pieces of blue candy, then the smallest amount of money he could have is <math>\text{lcm}{(12,14,15)} = 420</math> cents. Since a piece of purple candy costs <math>20</math> cents, the smallest possible value of <math>n</math> is <math>\frac{420}{20} = \boxed{\textbf{(B) } 21}</math>. | If he has enough money to buy <math>12</math> pieces of red candy, <math>14</math> pieces of green candy, and <math>15</math> pieces of blue candy, then the smallest amount of money he could have is <math>\text{lcm}{(12,14,15)} = 420</math> cents. Since a piece of purple candy costs <math>20</math> cents, the smallest possible value of <math>n</math> is <math>\frac{420}{20} = \boxed{\textbf{(B) } 21}</math>. | ||
+ | |||
+ | ~IronicNinja | ||
==Solution 2== | ==Solution 2== |
Revision as of 23:59, 17 February 2019
- The following problem is from both the 2019 AMC 10B #7 and 2019 AMC 12B #5, so both problems redirect to this page.
Contents
Problem
Each piece of candy in a store costs a whole number of cents. Casper has exactly enough money to buy either pieces of red candy,
pieces of green candy,
pieces of blue candy, or
pieces of purple candy. A piece of purple candy costs
cents. What is the smallest possible value of
?
Solution 1
If he has enough money to buy pieces of red candy,
pieces of green candy, and
pieces of blue candy, then the smallest amount of money he could have is
cents. Since a piece of purple candy costs
cents, the smallest possible value of
is
.
~IronicNinja
Solution 2
We simply need to find a value of that is divisible by
,
, and
. Observe that
is divisible by
and
, but not
.
is divisible by
,
, and
, meaning that we have exact change (in this case,
cents) to buy each type of candy, so the minimum value of
is
.
See Also
2019 AMC 10B (Problems • Answer Key • Resources) | ||
Preceded by Problem 6 |
Followed by Problem 8 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | ||
All AMC 10 Problems and Solutions |
2019 AMC 12B (Problems • Answer Key • Resources) | |
Preceded by Problem 4 |
Followed by Problem 6 |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | |
All AMC 12 Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.