An investment broker has 25 clients, each of which has invested in mut

Can we use a tic-tac-toe board in this question?

Bunuel, this question was spotted in GMAT Practice Exam 6.

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Added the tag. Thank you!

Olkka
we can use a tic tac toe board! In fact, thats how I solved mine
Consider something like this:
(apologies im not able to insert an image so bear with me!)

First we need to keep our perimeters clear. Our table's 2 rows are labelled Municipal bonds and no municipal bonds. The table's 2 columns are similarly labelled Mutual funds and no mutual funds. Keep slots for totals of the rows, columns and of course the total no. of clients at the bottom right (25).

After you have inserted 25, start inserting whatever other information we have.
1) 20 clients have invested in mutual - put this at the total of the mutual funds column

2) 18 clients have invested in municipal bonds - put this at the total of the municipal row.

3) Each client has invested in mutual, municipal or both- This tells us that the slot of those who have not invested in mutual and municipal is zero.

Alright, now we can inch forward step by step and fill in the neighboring slots. First of all, let's look at the totals of the columns. Our no mutual funds column is still empty but that can very quickly be fixed. A total of 25 minus 20 (mutual funds total) gives us 5.

Now that the "no mutual" column's total is 5, we can find those who have invested in municipal but not mutual (5 minus zero gives us 5).

Now it is very easy for us to find those who have invested in both types of funds: use the total of the municipal row (18) minus 5 (invested in municipal but not mutual) giving us 13!

Hope it helps Pls leave a kudos if it did!

13 is the right answer. 38-25=13.

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