ankithakhu wrote:

During a 7-year period the profits of Midas, Inc. changed by what percent from the sixth year to the seventh year?

(1) The profits of Midas, Inc. during the seventh year were 50 percent greater than the profits during the third year.

(2) The increase in the profits of Midas, Inc. was the same for each year during the 7-year period.

This is an interesting old question,But I think needs expert opinion.

we need to know the profits of 6th and 7th year in order to answer this question.

(1) The profits of Midas, Inc. during the seventh year were 50 percent greater than the profits during the third year.

Nothing about the sixth year so Insufficient

(2) The increase in the profits of Midas, Inc. was the same for each year during the 7-year period.

Initially I thought this was sufficient as profits of 6 and 7 year seemed to be same, but that is not so.

The original profits of 6 and 7 year may be different but increase may be same, hence we do not know that actual 6 and 7 year profits.

1+2

from 1

Let 3 year profit be x and 7 year profit is 1.5x still we know nothing about 6 year

from 2 : increase in profits were the same each year , so let the increase in profits be y each year

year ---- profit

3 ------- x

4 ------- x+y

5 ------- x+y+y = x+2y

6 ------- x+3y

7 ------- x+4y

Now we know 6 year profit is x+3y and 7 year profit is x+4y

also we know x+4y=1.5x ( 7 year profit is 1.5 times 3 year profit, we have taken 3 year profit to be x)

on solving x+4y=1.5x we get x= 8y

now 6 year profit is 11y ( from chart above )and 7 year profit is 12y

so profit % increase from 6 to 7 year \(\frac{12y-11y}{11y}*100 =\frac{100}{11} = 9.09\)

We know C is is the answer, but can any one tell me if I have arrived at the correct percentage change in profit?

Thanks

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- Stne