|
Question 406080: Hi i have two questions, one dealing with inequalities. Im only in pre algebra and i dont understand. Can you please answer this and maybe i will understand?
Solve the following inequality:
2 < -8s
Now for the second question its a word problem having to do with feet per second? Another person asked this same math question, but the answer was wrong!
QUESTION : ACCORDING TO THE GUINNESS BOOK OF WORLD RECORDS, THE PEREGRINE FALCON HAS A RECORD DIVING SPEED OF 168 MILES PER HOUR. WRITE THIS SPEED PER SOCOND.
Thankyou! Please respond quick.
Found 3 solutions by stanbon, Alan3354, josmiceli:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Solve the following inequality:
2 < -8s
Divide both sides by -8 to get:
-1/4 < s
Rewrite the result to get:
s > -1/4
========================
Now for the second question its a word problem having to do with feet per second? Another person asked this same math question, but the answer was wrong!
QUESTION :
--------------------------
ACCORDING TO THE GUINNESS BOOK OF WORLD RECORDS, THE PEREGRINE FALCON HAS A RECORD DIVING SPEED OF 168 MILES PER HOUR. WRITE THIS SPEED PER SECOND.
=======================
[168 (miles/hour)] * [1 hr/3600 sec]
---
= [168*1] / [1*3600](miles/sec)
---
= 0.04667 miles/second
=============================
Cheers,
Stan H.
===========
Answer by Alan3354(69443)  (Show Source):
You can put this solution on YOUR website! Solve the following inequality:
2 < -8s
Divide by 8
1/4 < -s
-s > 1/4
Divide by -1
s < -1/4 Dividing by negative changes to <
-------------------------------
Or look at it this way:
1/4 < -s
Add s
s + 1/4 < 0
Subtract 1/4
s < -1/4 Same answer.
------------------------
Now for the second question its a word problem having to do with feet per second? Another person asked this same math question, but the answer was wrong!
QUESTION : ACCORDING TO THE GUINNESS BOOK OF WORLD RECORDS, THE PEREGRINE FALCON HAS A RECORD DIVING SPEED OF 168 MILES PER HOUR. WRITE THIS SPEED PER SOCOND.
15 mph = 22 ft/second (You can calculate that or remember it)
60 mph = 1 mile/minute = 5280 ft/minute = 88 ft/sec
--> 15 mph = 22 ft/sec
--------------------
168 mph * 22/15 = 246.4 ft/second
Answer by josmiceli(19441)  (Show Source):
You can put this solution on YOUR website! Hi,
I'll explain this problem with a more simple problem that shows
the exact same idea.
OK, what you want to find is  . What is the given inequality telling you?
If 
then  true
-----------------
If 
then  true
-----------------
If 
then  not true
----------------
In fact, if is -1, -2, -3, -4, or any minus number more negative than  ,
the inequality is not true. It is true for any number that is more positive than
That includes the negative fractions like -1/3, -1/4, -1/5, etc. and also the
positive fractions like 1/3, 1/4, etc. and then it is true for all the positive numbers,
1, 2, 3, 4, etc.
--------------
Now I still want to find . The normal way to do this with an equality is to
divide both sides by
plus divided by minus is minus and
minus divided by minus is plus, so
and now just write this going from right to left
 this is the same thing
But what happened? I said the original inequality was true for all numbers
greater than , or, in other words,  .
Now I divided both sides by , and the result is telling me just the opposite.
This leads to a general rule:
------------------------------------------------------
Whenever you divide both sides of an inequality by a minus quantity,
you must reverse the inequality sign when you are done.
Following this law:
Now rewriting this from right to left:
Notice I reversed the inequality sign, and it is now true.
----------------
So, to solve your problem:
 (I reversed the inequality sign)
 (I just rewrote it going right to left)
This is true- try any number that is greater than or equal to  ,
and the inequality becomes false.
for example:
 not true
----------------
I hope all this helps and isn't too confusing.
|
|
|
| |
