Aptitude - Decimal Fraction - Discussion

@Vasu.

You reached till 127/99, Which is perfectly right, now to solve this further look at the options a) 1.20 and b) 1.2bar is no ways the answer.

Let's take c) 1.27bar .. solve this 1.27 bar can be written as 1+0.27 bar which is nothing but 1+27/99 now solve this you get 126/99 which is not what you got.

Now take option d) 1.28bar same as above this can be written as 1+0.28 bar which is 1+28/99 and solve this now, You get the Solution as 127/99 same as what you got. Hence option d)1.28bar is the right answer.

Hope it helped you.

@Naveen

when 3.87 - 2.59 dot takes place Hundred so simply write 387/100-259/100 but in numerator 87(bar) is their so to less one number in denominator 3.87-2.59.

(3 + 0.87) - (2 + 0.59),
(3 + 87/99) - (2 + 59/99),
3 + 87/99- 2 - 59/99,
Next, step to separate
(3 - 2) + (87/99 - 59/99),
(1) + ((87-59)/99),
1 + (28/99).
Next step comparing with answers all answer in a fraction, so change it as
1.28(bar).

Simple method.

3.87bar=3.878787 (bar numbers is repeated).
2.59bar=2.595959(bar number repeated) now subtract=1.282828(28 is repeated so put bar on that number so the answer is 1.28bar.

3.87-2.59.
(3+87÷99)-(2+59÷99),
(297+87)÷99 -(198+59)÷99,
(384÷99)-(257÷99),
127÷99.

I don't know where I am wrong, can anyone explain?

For those who are asking that why the numbers are divided by 99. Watch the important formulas section (converting a pure recurring decimal into vulgar fraction).

Bar upon the number indicates repeat that number. That is why we divide the number by 99. It's good idea.

@All.

If both the numbers are in same form then do the simple calculation.

3.87 - 2.59 = 1.28.

@Nagaraju.

Can we change the signs by opening the brackets as you explained in step 3 above?

Why we have divided the numbers with 99?

Do we do this with every number or is it a trick?

Why it is not like (387-3)/99 -(259-2)/99?

Then, 127/99,
Ans = 1.(bar of 27) or 1.27.