20. Mr. Sprengel has a total amount of 91 pens and pencils. The ratio of pens to pencils is 6:7. How many pencils does he have?

Mr. Sprengel has 49 pencils.

Step-by-step explanation:

We are given that Mr. Sprengel has 91 pens and pencils.

We are also given that the ratio of pens to pencils is 6:7.

Basically, the problem is telling us that for every 6 pens, there are 7 pencils.

Therefore, we can set up an equation and set our unknown (the amount of pencils) to be equal to x.

Now, we found our x. However, we need to plug this into a new equation and find how many pens and pencils Mr. Sprengel has.

Our new equations are:

In this case:

Therefore, let's solve these:

Now, finally, we need to insert these values into our newfound equation:

We get a true statement, so we have determined that Mr. Sprengel has: