grrr.. i have a test tommorow i dont get it
2006-09-20 18:07:44 · 7 answers · asked by koolchick134 2 in Education & Reference ➔ Homework Help
it is 105
2006-09-20 18:14:53 · answer #1 · answered by bubul 1 · 0⤊ 0⤋
If the original number "x" is decreased by 1/5 and the result is 84... look at it through an equation ->
X - 1/5X = 84
then simplify
X - X/5 = 84
find a common denominator (5)
and multiply to make both sides of the fraction proportional
5X - X
--------- = 84
5
then multiply both sides by 5 (to cancel out the denominator)
( 5 ) 5X - X
--- * -------- = 84 * ( 5 )
( 1 ) 5
simplify
5X - X = 420
simplify
4X = 420
divide each side to get "X" by itself
4X = 420
--- -----
4 4
X = 105 and that is the original number !
NOW WAIT! Don't forget to check your answer
go back to the orignal question....
X - X/5 = 84
(105) - (105) / 5 = 84
105 - 21 = 84
84 = 84 Yes! It works!
I hope I helped! I love math - that's why my major in college right now is based on math - > engineering! :D
2006-09-21 01:20:43 · answer #2 · answered by jessica 2 · 0⤊ 0⤋
Let the number be x
now x - 1/5 x = 84
multiplying throughout by 5 we get
5x - x = 420
or 4x = 420
so x = 420/4 = 105
check it out by decreasing 1/5 of 105 from itself, you get 84. So your answer is correct = the number is indeed 105
2006-09-21 01:10:51 · answer #3 · answered by young_friend 5 · 0⤊ 0⤋
The question translates into
x - (1x/5) = 84
Find the LCD on the left side (It is of course 5)
so 5x/5 - 1x/5 = 84 or
4x/5 = 84 Multiply both sides by 5 to eliminate fractions, resulting in
4x = 420
Now divide both sides by the four and you have 105
Check: 105 - (105/5) = 84?
105 - 21 = 84? Yes
2006-09-21 01:13:32 · answer #4 · answered by randyken 6 · 0⤊ 0⤋
x - 1/5 x = 84
84 x 5 = 420
5x - x = 420
4x = 420
x = 420/4 => x = 105
105 - (105 x 1/5) = 105 - 21 = 84
2006-09-21 01:20:34 · answer #5 · answered by Lopez D 1 · 0⤊ 0⤋
that would be 420,
this can be done by multiplying 84 with 5.
420/5 = 84
2006-09-21 01:10:42 · answer #6 · answered by Loz R 2 · 0⤊ 0⤋
x-1/5x=84,.....x-1/5x=4/5x=84,....x=5/4 x 84=105!!!!!!
2006-09-21 01:16:37 · answer #7 · answered by the withness 3 · 0⤊ 0⤋