Today’s SAT Challenge #001 | SATMath800
๐Ÿ”ฅ QUESTION OF THE DAY #001

Can You Solve It Without Losing Valuable Time?

Some SAT questions look intimidating because of long formulas. The key is to recognize the hidden structure before doing the algebra.

๐Ÿ‘น Repeating Monster
โฑ 2โ€“3 Minutes
โญโญโญ Medium
Solve the Question โ†“
Repeating Monster

The Repeating Monster

Long expressions look scary. Repeated expressions don’t have to.

๐Ÿ“˜ QUESTION OF THE DAY
โญโญโญ Medium

Try This Before You Scroll

The monthly payment \(m\) is given by

$$ m= \frac{ \left(\frac{k}{800}\right) \left(1+\frac{k}{800}\right)^t }{ \left(1+\frac{k}{800}\right)^t-1 } S $$

Which expression gives \(S\) in terms of \(m\), \(k\), and \(t\)?

A
$$ S= \frac{ \left(\frac{k}{800}\right) \left(1+\frac{k}{800}\right)^t }{ \left(1+\frac{k}{800}\right)^t-1 } m $$
B
$$ S= \frac{ \left(1+\frac{k}{800}\right)^t-1 }{ \left(\frac{k}{800}\right) \left(1+\frac{k}{800}\right)^t } m $$
C
$$ S= \frac{800}{k}m $$
D
$$ S= \frac{ \left(1+\frac{k}{800}\right)^t }{ \frac{k}{800} } m $$
๐Ÿง 

Your Turn

Before looking at the solution, challenge yourself to solve the problem under real SAT conditions.

1

Start a Timer

Give yourself about 2โ€“3 minutes.

2

Choose an Answer

Don’t worry if you’re unsure. Make your best choice.

3

Learn the Strategy

Then compare your thinking with the faster method.

๐ŸŽฏ Goal

This lesson is not just about getting the correct answer. It is about learning a strategy you can recognize on future SAT questions.

๐Ÿง  SAT Strategy #001

Before We Solve…

Instead of carrying the same long expression through every algebraic step, let’s simplify the problem first.

๐Ÿง  SAT Strategy #001

๐Ÿ‘น Meet the Repeating Monster

Before doing any algebra, look carefully at the equation. Can you spot something that appears more than once?

$$ \left(1+\frac{k}{800}\right)^t $$

This expression appears repeatedly. Every time you rewrite it, you increase the chance of making a mistake.

Repeating Monster

๐Ÿ‘น The Repeating Monster

When a long expression appears again and again, don’t carry it everywhere. Give it a temporary name.


Hide the Monster

Let

$$ X= \left(1+\frac{k}{800}\right)^t $$

Now replace every occurrence of that expression with \(X\). The scary equation suddenly becomes much simpler.

$$ m= \frac{\left(\frac{k}{800}\right)X} {X-1} S $$
๐Ÿ’ก Dr. Aytekin Tip: The SAT is not testing whether you can rewrite the same long expression five times. It is testing whether you recognize a simpler way to think.
โšก Strategy in Action

Now Solve the Smaller Problem

After hiding the monster, the algebra becomes much cleaner.

1

Start Here

$$ m= \frac{\left(\frac{k}{800}\right)X} {X-1} S $$
โ†“
2
2

Isolate \(S\)

Multiply both sides by

$$ \frac{X-1} {\left(\frac{k}{800}\right)X} $$
โ†“
$$ S= \frac{X-1} {\left(\frac{k}{800}\right)X} m $$
โ†“
3

Replace \(X\)

$$ X= \left(1+\frac{k}{800}\right)^t $$

โœ… Final Expression

$$ S= \frac{ \left(1+\frac{k}{800}\right)^t-1 }{ \left(\frac{k}{800}\right) \left(1+\frac{k}{800}\right)^t } m $$
Correct Answer: B

๐Ÿง  What Actually Saved Time?

The algebra wasn’t difficult. The repeated expression made the work look complicated. By replacing it with a temporary variable, you reduced the visual clutter and made the structure easier to see.

๐Ÿง  TAKEAWAY

Remember This Strategy

The algebra wasn’t difficult. The repeated expression made it look difficult.

๐Ÿ‘€

Spot It

Look for expressions that appear repeatedly.

๐Ÿ‘น

Name It

Give the repeated expression a temporary name.

๐ŸŽฏ

Solve It

Work with the simpler equation, then substitute back.

๐Ÿš€ STRATEGY TOOLBOX

Strategy Unlocked

Every Question of the Day teaches one reusable SAT strategy. Collect strategiesโ€”not just formulas.

Repeating Monster

๐Ÿ‘น Hide the Monster

When a long expression appears multiple times, replace it with a temporary variable before solving.

โœ… Strategy Learned

Coming Next

๐Ÿ

Negative Sign Snake

๐Ÿงฎ

Fraction Monster

๐ŸŽญ

Disguise Monster

๐ŸŽฏ

Trap Monster

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