Aptitude - Percentage - Discussion

I'm unable to understand the answer.

The answer must be 20.

Why should we again calculate tax on tax payment?

As the question ask for cost of tax free items, we have to deduct the cost of taxable items and the tax imposed them (tax and taxable cost are included in the total cost).

How 6%of x = 30/100?

@Sanjeev.

Please, explain how to simplify the equation 1 and 2.

Table - Chair
15 - 5

By selling the chairs at 10% loss and the table at 10% profit, a total of 5% profit is made.

5%20 * 400 = 100 So cp of chair is Rs 100.

Lets say I purchased of Rs. Y (before paying tax) and the total of Rs. Y + tax (after paying tax)

Now, Y + tax = 25.

After spending, calculating 6% as, 5rs. means there is a 5rs. item on which I paid Rs.30 as the tax.

Thus: Y + Tax = 25.
That is: Y + .30 = 25,
or Y = 24.70.

Now, the items originally without paying tax were of Rs. 24.70. (that is I didn't pay the tax)
as 5 Rs item it taxable. Thus the item which is not taxable is : 24.70 - 5.00 = 19.70.

Why 100/6 is multiplied to find the value of x?

In the question. They have asked the cost of tax-free items. So in total purchased things, there will be things which are tax-free and the others will applied tax.

So, the tax applied to the items on which 6% TAX APpIES is 30p. So this tax applied the item which costs Rs. 5 as mentioned above. Then subtracting 5 + 0.3 from Rs. 25 we get Rs. 19.7.

Hope at least now you understood.

The solution becomes:

Rs. 25= cost of Tax-free items + cost of taxable items + tax on taxable items.

.... 25 = 19.70 + 5 + 0.30.

@Dezal.

Solve it through vein diagram.
60 + 50 = 110.
10 is extra count and it is the number of students who passed in both subject.