WORD PROBLEMS LEADING TO SIMPLE ALGEBRAIC FRACTIONS
What We Mean by “Word Problems Leading to Simple Algebraic Fractions”
A word problem is a story or real-life situation written in words, which must be converted into mathematical form.
A simple algebraic fraction means a fraction whose numerator or denominator includes algebraic terms (letters or variables).
So, this topic teaches us how to read a problem, write it as an algebraic fraction, and then solve it.
Example:
“One-third of a number is 10.” → Equation: (1/3)x = 10
“Amanda spent 2/5 of her money and has ₦60 left.” → Equation: (2/5)x + 60 = x
Why We Study This
- To use algebra in real life problems.
- To practice translating words into algebraic fractions.
- To improve equation-solving skills involving fractions.
- To understand fractions better through applications.
- Because it is an important topic for exams (BECE, school tests).
What Students Should Be Able To Do
- Identify the unknown in a problem and represent it with a letter.
- Translate the word problem into an algebraic fraction or equation.
- Solve for the unknown and simplify if needed.
- Check that the answer makes sense in the context of the problem.
Steps / Strategy for Solving Word Problems That Lead to Algebraic Fractions
- Read the problem carefully and understand what is given and required.
- Let the unknown quantity be represented by a variable (x, y, n, etc.).
- Translate the problem into an algebraic equation (often with fractions).
- Manipulate the equation and clear denominators if necessary.
- Simplify and solve for the unknown.
- Substitute back to verify the correctness of the answer.
- Write the final answer in words.
Key Ideas / Tips Students Should Know
- “One-third of x” means (1/3)x.
- Multiply both sides by the denominator to clear fractions.
- Look out for words like “left,” “spent,” “remaining,” etc.
- Denominators must not be zero.
- Always check your answer by substitution.
problems Examples (with Steps)
Example 1: One-third of a number is 10. What is the number?
- Let the number be x.
- Equation: (1/3)x = 10.
- Multiply both sides by 3 → x = 30.
- Answer: 30.
Example 2: Amanda spent (2/5) of her money and has ₦60 left. How much did she have originally?
- Let her original money be x.
- Equation: x - (2/5)x = 60.
- Simplify: (3/5)x = 60.
- Multiply both sides by 5 → 3x = 300.
- Divide by 3 → x = 100.
- Answer: ₦100.
Example 3: A pipe can fill 1/6 of a tank in one hour. How long to fill the whole tank?
- Let time = t hours.
- (1/6)t = 1.
- Multiply both sides by 6 → t = 6.
- Answer: 6 hours.
Example 4: (3/4) of a number minus 5 equals 7. Find the number.
- Let the number be x.
- (3/4)x - 5 = 7.
- (3/4)x = 12.
- Multiply both sides by 4 → 3x = 48.
- x = 16.
- Answer: 16.
Example 5: A total of ₦x is shared so that 1/3 goes to A, 1/4 to B, and ₦30 remains for C. Find x.
- Let total = x.
- Equation: x - [(1/3)x + (1/4)x] = 30.
- Find LCM of 3 and 4 = 12 → (4/12)x + (3/12)x = (7/12)x.
- x - (7/12)x = 30 → (5/12)x = 30.
- Multiply both sides by 12 → 5x = 360.
- x = 72.
- Answer: ₦72.
Example 6: (2/5) of a number plus 8 equals 20. Find the number.
- Let the number be x.
- (2/5)x + 8 = 20.
- (2/5)x = 12.
- Multiply both sides by 5 → 2x = 60.
- x = 30.
- Answer: 30.
Common Pitfalls / Mistakes Students Make
- Misreading key words like “of,” “left,” or “remaining.”
- Forgetting to multiply both sides when clearing fractions.
- Leaving denominators zero or answers unsimplified.
- Failing to check the final answer in the problem.