Comparing Rational Forms

Help Questions

SSAT Upper Level: Quantitative › Comparing Rational Forms

Questions 1 - 9
1

Which of the following lists the values $$\frac{5}{8}$$, $$62%$$, and $$0.627$$ in ascending order?

$$62% < \frac{5}{8} < 0.627$$

$$\frac{5}{8} < 62% < 0.627$$

$$\frac{5}{8} < 0.627 < 62%$$

$$0.627 < \frac{5}{8} < 62%$$

Explanation

Convert all to decimals: $$\frac{5}{8} = 0.625$$, $$62% = 0.62$$, and $$0.627$$ stays as is. Ordering from least to greatest: $$0.62 < 0.625 < 0.627$$, which corresponds to $$62% < \frac{5}{8} < 0.627$$. Choice A incorrectly assumes the fraction is smallest. Choice C reverses the order. Choice D incorrectly places the decimal between the fraction and percent.

2

A student claims that $$\frac{3}{7} > 0.42$$ because $$\frac{3}{7} = 0.428571...$$ and $$0.428571 > 0.42$$. What is wrong with this reasoning?

The reasoning is flawed because $$\frac{3}{7}$$ cannot be compared directly to $$0.42$$

The student correctly converted $$\frac{3}{7}$$ to decimal form and the comparison is valid

The student's conversion is correct, but $$0.428571... < 0.43$$, so more precision is needed

The student made an error; $$\frac{3}{7} = 0.42\overline{857142}$$, not $$0.428571$$

Explanation

When comparing fractions and decimals, you need to convert one form to the other and then make an accurate comparison. This question tests whether you can identify valid mathematical reasoning.

Let's verify the student's work step by step. To convert $$\frac{3}{7}$$ to decimal form, you divide 3 by 7. Performing this division gives you 0.428571428571..., where the digits 428571 repeat indefinitely. The student correctly identified this decimal representation. Now, comparing 0.428571... to 0.42: since 0.428571... is indeed greater than 0.42 (the additional digits 8571... make it larger), the inequality $$\frac{3}{7} > 0.42$$ is true. The student's reasoning is mathematically sound.

Looking at the wrong answers: Answer A suggests the reasoning fails because 0.428571... < 0.43, but this is irrelevant—the comparison was with 0.42, not 0.43. Answer B claims the decimal conversion is wrong, stating it should be $$0.42\overline{857142}$$, but this is actually the same value as 0.428571... (just different notation for the repeating decimal). Answer D incorrectly suggests that fractions and decimals cannot be compared directly, when in fact this is a standard mathematical operation once you convert to the same form.

The correct answer is C because the student performed both the conversion and comparison correctly.

Study tip: When checking decimal conversions of fractions, remember that repeating decimals are exact values, not approximations. Always verify a few decimal places beyond what you're comparing to ensure accuracy.

3

If $$x = 0.4\overline{5}$$ and $$y = \frac{41}{90}$$, which statement about $$x$$ and $$y$$ is true?

$$x < y$$ because $$0.4\overline{5} < 0.456$$ and $$\frac{41}{90} > 0.456$$

$$x < y$$ because the decimal representation is always less than the fraction

$$x = y$$ because both represent the same rational number

$$x > y$$ because repeating decimals are always greater than fractions

Explanation

Convert $$x = 0.4\overline{5}$$ to a fraction: Let $$x = 0.4555...$$ Then $$10x = 4.555...$$ and $$100x = 45.555...$$ So $$100x - 10x = 45.555... - 4.555... = 41$$, giving $$90x = 41$$, so $$x = \frac{41}{90}$$. Therefore $$x = y$$. Choices A and D make false generalizations about the relationship between decimals and fractions. Choice C incorrectly assumes $$0.4\overline{5} < 0.456$$, when actually $$0.4\overline{5} = 0.4555... > 0.456$$.

4

Three students calculated the same expression and got $$\frac{7}{12}$$, $$58\frac{1}{3}%$$, and $$0.583\overline{3}$$. How many of these answers are correct?

Only one of the answers is correct

All three answers are different values

Only two of the answers are correct and equivalent

All three answers are correct and equivalent

Explanation

Convert all to the same form to compare: $$\frac{7}{12} = 0.58\overline{3} = 0.583\overline{3}$$. To convert to percent: $$\frac{7}{12} \times 100% = \frac{700}{12}% = 58\frac{4}{12}% = 58\frac{1}{3}%$$. All three expressions represent the same value. Students might incorrectly think the repeating decimal is different from the fraction, or miscalculate the percentage conversion.

5

A recipe calls for $$\frac{3}{8}$$ cup of sugar. Maria has $$0.4$$ cups of sugar available. Which statement is true?

Maria has $$\frac{1}{40}$$ cup more sugar than needed

Maria has exactly enough sugar for the recipe

Maria has $$\frac{1}{8}$$ cup less sugar than needed

Maria has $$0.025$$ cups more sugar than needed

Explanation

First, convert $$\frac{3}{8}$$ to decimal: $$\frac{3}{8} = 0.375$$. Maria has $$0.4$$ cups, so she has $$0.4 - 0.375 = 0.025$$ cups extra. Converting $$0.025$$ to a fraction: $$0.025 = \frac{25}{1000} = \frac{1}{40}$$. Choice A is wrong because $$0.4 \neq 0.375$$. Choice C gives the correct numerical difference but in decimal form, not fraction form as stated in choice B. Choice D is wrong because Maria has more, not less sugar.

6

The value $$\frac{7}{11}$$ lies between which pair of benchmark percentages?

Between $$63%$$ and $$64%$$

Between $$60%$$ and $$65%$$

Between $$65%$$ and $$70%$$

Between $$64%$$ and $$65%$$

Explanation

Convert $$\frac{7}{11}$$ to a percentage: $$\frac{7}{11} = 0.636363... = 63.\overline{63}%$$. This is approximately $$63.64%$$. Among the choices, this falls between $$60%$$ and $$65%$$. Choice B is too narrow a range, though $$63.64%$$ does fall between $$63%$$ and $$64%$$, the question asks for benchmark percentages and choice A provides the appropriate broader range. Choice C ($$64%$$ to $$65%$$) doesn't contain $$63.64%$$. Choice D is too high.

7

Which expression has the greatest value?

$$0.75$$ increased by $$\frac{2}{3}$$ of itself

$$\frac{2}{3}$$ increased by $$75%$$ of itself

$$\frac{2}{3}$$ of $$75%$$

$$75%$$ of $$\frac{2}{3}$$

Explanation

Calculate each: A) $$\frac{2}{3} \times 0.75 = \frac{2}{3} \times \frac{3}{4} = \frac{1}{2} = 0.5$$. B) $$0.75 \times \frac{2}{3} = \frac{3}{4} \times \frac{2}{3} = \frac{1}{2} = 0.5$$. C) $$0.75 + \frac{2}{3} \times 0.75 = 0.75(1 + \frac{2}{3}) = 0.75 \times \frac{5}{3} = \frac{5}{4} = 1.25$$. D) $$\frac{2}{3} + 0.75 \times \frac{2}{3} = \frac{2}{3}(1 + 0.75) = \frac{2}{3} \times 1.75 = \frac{7}{6} \approx 1.167$$. Choice C has the greatest value at $$1.25$$.

8

A store offers a discount that reduces the original price by $$\frac{2}{9}$$. If this is equivalent to a $$22.\overline{2}%$$ discount, what can you conclude?

The store's calculation is correct since both represent the same discount

Both calculations are wrong; $$\frac{2}{9}$$ cannot be expressed as a repeating decimal percentage

The store made an error; $$\frac{2}{9}$$ equals approximately $$22.22%$$, not $$22.\overline{2}%$$

The store made an error; the percentage should be $$\frac{200}{9}%$$

Explanation

When you encounter questions about equivalent representations of fractions and percentages, you need to verify whether different forms truly represent the same value through precise conversion.

To determine if $$\frac{2}{9}$$ equals $$22.\overline{2}%$$, convert the fraction to a decimal by dividing: $$2 \div 9 = 0.222...$$ or $$0.\overline{2}$$. To express this as a percentage, multiply by 100: $$0.\overline{2} \times 100 = 22.\overline{2}%$$. The notation $$22.\overline{2}%$$ means the digit 2 repeats infinitely (22.2222...%), which is exactly what we get from $$\frac{2}{9}$$. Therefore, the store's calculation is mathematically correct.

Choice A is wrong because $$\frac{2}{9}$$ absolutely can be expressed as a repeating decimal percentage—we just demonstrated this. Choice B contains a critical misunderstanding: $$22.22%$$ (which terminates) is actually an approximation, while $$22.\overline{2}%$$ (which repeats infinitely) is the exact value. The store used the precise notation, not an approximation. Choice C suggests $$\frac{200}{9}%$$, but this equals $$22.\overline{2}$$, which would mean $$22.\overline{2}%$$ of a percent—a much smaller value than intended.

The correct answer is D because both representations are mathematically equivalent.

Study tip: Master the bar notation for repeating decimals ($$\overline{2}$$ means the 2 repeats forever). This notation often appears on the SSAT to test precision versus approximation. Always convert fully rather than rounding when checking equivalencies.

9

A number is $$25%$$ larger than $$\frac{4}{5}$$. Which expression represents this number?

$$\frac{4}{5} + 0.25$$

Both B and C represent the same number

$$\frac{4}{5} + \frac{1}{4} \times \frac{4}{5}$$

$$1.25 \times \frac{4}{5}$$

Explanation

A number that is $$25%$$ larger than $$\frac{4}{5}$$ equals $$\frac{4}{5} + 0.25 \times \frac{4}{5}$$. This can be written as $$\frac{4}{5}(1 + 0.25) = 1.25 \times \frac{4}{5}$$ (choice B). Since $$25% = \frac{1}{4}$$, it can also be written as $$\frac{4}{5} + \frac{1}{4} \times \frac{4}{5}$$ (choice C). Choice A incorrectly adds $$0.25$$ instead of $$25%$$ of $$\frac{4}{5}$$. Both B and C are mathematically equivalent and correct.