Question

the cost of item is increased by 2times, after the increasing, the item costs 2 times expensive than the first, what percent is the amount increased in the first time, if the second time the amount is increased by 25%

And the answer is 60 !!
so how to solve this ? I tried to solve it and i got 12.5 ! so please with a explanation write the steps down for me

Answer 1

Conditions

the cost of item is increased by 2 times, after the increasing, the item costs 2 times expensive than the first, what percent is the amount increased in the first time, if the second time the amount is increased by 25%

Solution

Let's item's value is X from the very beginning.

After first time it was increased by A%. The new cost is $X^*(1+A)$.

After second time it was increased by 25% (relatively to a previous price, which is equal to $X^*(1+A)$). So the last value is $X^*(1+A)(1+0,25)$. And this is 2 times expensive that the first price

$$X(1+A) - 1.25 = 2X$$ $$1 + A = \frac{2}{1.25} = 1.6$$ $$A = 0.6 = 60\%$$

Answer: First time percent was 60%.