Motoi I.
asked 12/29/17Why 10/3 = 3.(33) and 3.(33) × 3 =9.(99) instead of 10 ? Can someone explain?
A little math dilemma
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4 Answers By Expert Tutors
Andy C. answered 12/29/17
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4.9
(27)
Math/Physics Tutor
Let x = 3 and 1/3 = 3.3 <---- the three repeats forever
3X = 3 x (3 and 1/3) = 3 x 10/3 <--- changes to improper fraction
= 3/1 x 10/3
= 30/3
= 10 <---- the three cancels out in the previous step
------------------------------------------------------------------------
= 10
0.333333... = 0.3 + 0.03 + 0.003 + 0.0003 + ...
This is a geometric series with common ratio 0.1.
The sum of the series is a1 / (1-r) where a1is the first term.
So, 0.333... = 0.3 / (1 - 0.1) = 0.3 / 0.9 = 3/9 = 1/3
Therefore, (3.333...)(3) = (3 + 0.333...)(3) = (3 + 1/3)(3) = (10/3)(3) = 10
Vikki P. answered 12/29/17
Tutor
New to Wyzant
Professional, Experienced, Certified Teacher for Youth and Adults
I found out this:
10/3 = 3.333333333333......-The "3" repeats forever.
WHILE THIS REPEATING NUMBER IS IN THE CALCULATOR,if you type "* [times] 3", then it will equal 10.
BUT, if you retype 3.333333333333333, this number ENDS after the decimal on the 15th 3. THIS number "* 3" will equal the repeating 9.9999999999999999.
I hope this clarifies this for you.
Mark M. answered 12/29/17
Tutor
5.0
(278)
Mathematics Teacher - NCLB Highly Qualified
10/3 = 3.333333333333333333333333333333333333333333333333333333333333333333333333333333333333333...
It never ends!
Therefore
(3)(3.333333333333333333333333333333333333333333333333333333333333333333333333333333333333333...) =
9.999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999...
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Andrew M.
12/29/17