TJ Prep Problems

TJ Prep practice problems  for our students and readers. The problems provide a very small sampling of what Optimal TJ Prep students work with.

A Geometry Problem for TJ/AOS/Blair Test Prep (Difficult). Target Time 60 - 120 seconds.

There are four cylindrical containers A ( r = 8, h = 16, B (r = 4, h = 8), C and D. Containers C and D are identical to containers B and A respectively. Container A is completely filled with a "nonvolatile" liquid; containers B, C and D are empty.  Content of container A is poured to completely fill containers B and C.   Half of the remaining fluid in container A is poured into cylinder D. What is the height of fluid in container D?

Note. The target time assumes that you will do it step by step using formula taught in your prealgebra class. However, it is possible to solve it without using pencil and paper. See if you can do it? 

Science Trivia- If you read the problem carefully, you must be wondering why the word nonvolatile is put in quotation marks. If you can't think of a good answer, you can ask me by emailing to learn@tripathi.com.

An Algebra/Arithmetic Problem for TJ/AOS/Blair Test Prep (Medium). Target Time. 30-45 seconds.

Cashews cost $9/Kg and peanuts cost $5/Kg. To make a 300 Kg mixture of cashews and peanuts which will sell for $6.50/Kg, how many Kg of cashews and peanuts will be required? Assume there is no cost for mixing. Note. Although the specified target time is 30-45 seconds, it is possible to solve the problem in 20 seconds or less after you read the question; see if you can solve this question in 20 seconds after reading it!

A Difficult Geometry Problem for TJ Test Prep. Target Time. 20 seconds to 2 minutes.

ABC is an equilatera triangle. AP = AQ = BU = BT = CS = CR = 1/3 of AB. .

I. Ratio of the area of the hexagon PQRSTU to the area of triangle ABC?

2. Ratio of the area of the hexagon to the sum of the areas of the equilateral triangles APQ, BUT and CRS?

Note. If you use the techniques taught in geometry class, you may take 2 to 4 minutes per part, however, if you have developed appropriate, geometry "common sense" or "geometric maturity", you can solve each part in 20-30 seconds.  I invite you to solve this two-part problem to check on geometric maturity.

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A Rate-Work Problem for TJ Test Prep. Target Time. 30-40 seconds.

Sela and Neela are painter robots. Sela takes 48 Hrs to paint your house. If Sela and Neela (a trainee) work together, they can paint your house in 40 Hrs. Working alone, Neela will take how many Hrs to paint your house?

 

Note: Ark, thank you for pointing out the typo in the first version of of the problem. I appreciate all corrections.