Difference between revisions of "1986 AJHSME Problems/Problem 1"

m (Solution)
 
(One intermediate revision by one other user not shown)
Line 1: Line 1:
 
==Problem==
 
==Problem==
  
In July 1861, <math>366</math> inches of rain fell in Cherrapunji, India.  What was the average rainfall in inches per hour during that month?
+
In July 1861, <math>366</math> inches of rain fell in Cherrapunji, India.  What was the [[average]] rainfall in inches per hour during that month?
  
 
<math>\text{(A)}\ \frac{366}{31\times 24}</math>
 
<math>\text{(A)}\ \frac{366}{31\times 24}</math>
Line 15: Line 15:
 
==Solution==
 
==Solution==
  
We can express the number of inches of rain in a ratio, <math>\frac{366 \text{ inches}}{1\text{  month}}</math>. We need to find to find the number of hours, but first we need to find the number of days. We know there are 31 days in July, so we get <cmath>\frac{366 \text{ inches}}{1 \text{ month}} \times \frac{1 \text{ month}}{31 \text{ days}}</cmath>
+
We can express the number of inches of rain in a [[ratio]], <math>\frac{366 \text{ inches}}{1\text{  month}}</math>. We need to find to find the number of hours, but first we need to find the number of days. We know there are 31 days in July, so we get <cmath>\frac{366 \text{ inches}}{1 \text{ month}} \times \frac{1 \text{ month}}{31 \text{ days}}</cmath>
  
 
We know there are 24 hours in a day, so we get <cmath>\frac{366 \text{ inches}}{1 \text{ month}} \times \frac{1 \text{ month}}{31 \text{ days}} \times \frac{1 \text{ day}}{24 \text{ hours}}</cmath>
 
We know there are 24 hours in a day, so we get <cmath>\frac{366 \text{ inches}}{1 \text{ month}} \times \frac{1 \text{ month}}{31 \text{ days}} \times \frac{1 \text{ day}}{24 \text{ hours}}</cmath>
Line 25: Line 25:
 
==See Also==
 
==See Also==
  
[[1986 AJHSME Problems]]
+
{{AJHSME box|year=1986|before=First<br>Problem|num-a=2}}
 +
[[Category:Introductory Algebra Problems]]
 +
{{MAA Notice}}

Latest revision as of 20:02, 3 July 2013

Problem

In July 1861, $366$ inches of rain fell in Cherrapunji, India. What was the average rainfall in inches per hour during that month?

$\text{(A)}\ \frac{366}{31\times 24}$

$\text{(B)}\ \frac{366\times 31}{24}$

$\text{(C)}\ \frac{366\times 24}{31}$

$\text{(D)}\ \frac{31\times 24}{366}$

$\text{(E)}\  366\times 31\times 24$

Solution

We can express the number of inches of rain in a ratio, $\frac{366 \text{ inches}}{1\text{  month}}$. We need to find to find the number of hours, but first we need to find the number of days. We know there are 31 days in July, so we get \[\frac{366 \text{ inches}}{1 \text{ month}} \times \frac{1 \text{ month}}{31 \text{ days}}\]

We know there are 24 hours in a day, so we get \[\frac{366 \text{ inches}}{1 \text{ month}} \times \frac{1 \text{ month}}{31 \text{ days}} \times \frac{1 \text{ day}}{24 \text{ hours}}\]

And simplifying gets us $\dfrac{366 \text{ inches}}{31 \times 24 \text{ hours}}$, which is $\boxed{\text{A}}$.

Note that in the simplifying step, we noted that the month and day units cancel, leaving us with only inches per hour.

See Also

1986 AJHSME (ProblemsAnswer KeyResources)
Preceded by
First
Problem
Followed by
Problem 2
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

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. AMC logo.png