Pete recently bought whiteboard supplies for employees in his office. He spent $140 on whiteboards, markers, and erasers. The markers came in packs of 5, which cost $6 per pack. One (1) eraser was 1/3 of the cost of 1 pack of markers and 1 whiteboard was 5 times the cost of 1 eraser. If Pete purchased 56 items in total, including 35 markers, then how many whiteboards did he buy?

number of markers ..... 35 , so 7 packs

number of erasers ...... x
number of whiteboards .... y
cost of markers ------ $6 per pack
cost of erasers ------ $2
cost of whiteboards ---- $10

x+y+35 = 56
x + y = 21 **
7(6) + 2x + 10y = 140
2x + 10y = 98
x + 5y = 49 ***

subtract ** from ***
4y = 28
y = 7

carry on .....

Well, let's do some math while keeping a straight face, shall we?

First, let's calculate the cost of the erasers. Since one eraser is 1/3 of the cost of one pack of markers, and one pack of markers is $6, we can conclude that one eraser costs $6/3 = $2.

Now, let's determine the cost of one whiteboard. We know that one whiteboard is 5 times the cost of one eraser, so one whiteboard costs $2 x 5 = $10.

So far, we've determined that the cost of one whiteboard is $10 and the cost of one pack of markers is $6. Now, let's figure out how many packs of markers Pete bought. If 35 markers were purchased and each pack contains 5 markers, then Pete bought a total of 35/5 = 7 packs of markers.

Now, let's calculate the total cost of the markers. Since each pack of markers costs $6 and Pete bought 7 packs, we can conclude that the cost of the markers is $6 x 7 = $42.

Finally, we can calculate the cost of the whiteboards. If the total cost of all the supplies including the markers and erasers is $140, and we know the cost of the markers is $42, then the cost of the whiteboards is $140 - $42 = $98.

Since one whiteboard costs $10, Pete must have purchased $98/$10 = 9.8... whiteboards.

Now, we can't have a fraction of a whiteboard, can we? So, Pete must have bought a total of 9 whiteboards.

So, to answer your question, Pete bought a grand total of 9 whiteboards. Ta-da!

Let's break down the information given step by step:

Step 1: Determine the cost of one pack of markers.
The markers came in packs of 5, which cost $6 per pack. So, the cost of one pack of markers is $6.

Step 2: Calculate the cost of one eraser.
One eraser was 1/3 of the cost of 1 pack of markers. Since one pack of markers costs $6, the cost of one eraser is 1/3 * $6 = $2.

Step 3: Find the cost of one whiteboard.
One whiteboard was 5 times the cost of 1 eraser. Since the cost of one eraser is $2, the cost of one whiteboard is 5 * $2 = $10.

Step 4: Determine the number of markers purchased.
Pete purchased 35 markers in total.

Step 5: Calculate the total cost of the markers.
Since the cost of one pack of markers is $6, the total cost of the markers is (35/5) * $6 = $42.

Step 6: Determine the number of whiteboards purchased.
Pete spent a total of $140 on whiteboard supplies, and the total cost of the markers is $42. Therefore, the cost of the whiteboards must be $140 - $42 = $98.

Step 7: Calculate the number of whiteboards purchased.
Since the cost of one whiteboard is $10 and the total cost of the whiteboards is $98, the number of whiteboards Pete bought is $98 / $10 = 9 whiteboards.

Therefore, Pete bought 9 whiteboards.

To find out how many whiteboards Pete bought, we need to analyze the given information step by step.

Let's assign variables to the unknowns:
Let x be the number of whiteboards Pete bought.
Let y be the cost of one eraser.

From the given information:
The markers came in packs of 5, costing $6 per pack. So, the cost of one marker is $6/5.
The eraser costs 1/3 of the cost of one pack of markers. So, the cost of one eraser is (1/3) * ($6/5).
One whiteboard is 5 times the cost of one eraser. So the cost of each whiteboard is 5 * (1/3) * ($6/5) = $2.

Let's set up the equations based on the given information:
The cost of all the markers is 35 * ($6/5) = $42.
The cost of all the erasers is 35 * (1/3) * ($6/5) = $14.

We know that Pete spent a total of $140, so the cost of the whiteboards is:
$140 - $42 (for markers) - $14 (for erasers) = $84.

Since each whiteboard costs $2, the number of whiteboards Pete bought is:
Number of whiteboards, x = $84 / $2 = 42.

Therefore, Pete bought 42 whiteboards.