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 Word Problem (Medium). Target Time

The design for a novel flubber Robot (with human touch) calls for its composition to be 24% metal, 12% ceramic, 32% plastic and 32% a special alloy. If assembly of 1 such robot calls for 6 Kg of ceramic, 1) how many Kg of plastic will be required, and 2) what will be the weight of a fully assembled robot?

A Difficult TJ Prep/Blair Prep Problem. Target Time 40-60 seconds.

Jack and Jill have identical candles. Each candle burns completely in 6
Hrs at a uniform rate. Jack lit his candle at 6 PM while Jill lit her candle at 7 PM. At what time
Jill's candle will be exactly 50% taller than Jack's candle? You can solve it by making an equation or by making a table; try both ways!

A Probability Problem (Medium). Target Time 30-40 seconds.

At the TJHSST (TJ) graduation party, there are nearly 480 students. What is the probability that 1) at least five students have the same birth month and date?, 2) at least ten students have the same birth day (Mon-Sun)?, and 3) at least two students have the same birthday (matching birthday -  date, month and year?