Difference between revisions of "2018 AMC 8 Problems/Problem 12"
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<math>\textbf{(A) }5:50\qquad\textbf{(B) }6:00\qquad\textbf{(C) }6:30\qquad\textbf{(D) }6:55\qquad \textbf{(E) }8:10</math> | <math>\textbf{(A) }5:50\qquad\textbf{(B) }6:00\qquad\textbf{(C) }6:30\qquad\textbf{(D) }6:55\qquad \textbf{(E) }8:10</math> | ||
{{AMC8 box|year=2018|num-b=11|num-a=13}} | {{AMC8 box|year=2018|num-b=11|num-a=13}} | ||
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| + | == Solution == | ||
| + | We see that every 35 minutes the clock passes, the watch passes 30 minutes. That means that the clock is <math>\frac{7}{6}</math> times faster than the watch, so when the car clock passes 7 hours, the watch has passed 6 hours, meaning that the time would be <math>\boxed{\textbf{(B) }6:00}</math> | ||
| + | {{AMC8 box|year=2018|num-b=11|num-a=3}} | ||
Revision as of 13:16, 21 November 2018
Problem 12
The clock in Sri's car, which is not accurate, gains time at a constant rate. One day as he begins shopping he notes that his car clock and his watch (which is accurate) both say 12:00 noon. When he is done shopping, his watch says 12:30 and his car clock says 12:35. Later that day, Sri loses his watch. He looks at his car clock and it says 7:00. What is the actual time?
| 2018 AMC 8 (Problems • Answer Key • Resources) | ||
| Preceded by Problem 11 |
Followed by Problem 13 | |
| 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 AJHSME/AMC 8 Problems and Solutions | ||
Solution
We see that every 35 minutes the clock passes, the watch passes 30 minutes. That means that the clock is 
times faster than the watch, so when the car clock passes 7 hours, the watch has passed 6 hours, meaning that the time would be 
| 2018 AMC 8 (Problems • Answer Key • Resources) | ||
| Preceded by Problem 11 |
Followed by Problem 3 | |
| 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 AJHSME/AMC 8 Problems and Solutions | ||
