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Algebraic Fractions and Rational Expressions — Free MYP4 Mathematics (Extended) Practice Questions
1QuestionAlgebraic Fraction Word ProblemsConcept Practice
4 marks~6 minCriterion A
A water treatment plant monitors chemical concentration using the rational function
C(t)=t+12t+4
where C is the concentration in milligrams per litre and t is the time in hours after treatment begins. The safe upper limit for the chemical is 2.6 mg/L.
a
Calculate C(3), simplifying your answer fully. [2]
b
Advise the plant operator whether the concentration at t=3 hours requires immediate action, justifying your answer with reference to the safe limit. [2]
Solutions
2QuestionAdding and Subtracting with Common DenominatorsAssessment Practice
4 marks~6 minCriterion D
A bakery models its average cost per batch of cupcakes (in dollars) using the expression
x1200+x800
where 1200 dollars represents ingredient costs, 800 dollars represents labour costs, and x is the number of batches produced.
a
Simplify x1200+x800 to a single rational expression. [1]
b
The bakery owner uses x2000 to decide how many batches to produce each week. Interpret this expression in the context of the bakery: explain what it reveals about cost behaviour, and advise the owner whether this model alone is sufficient to support production decisions. [3]
Solutions
3QuestionMultiplying and Dividing Algebraic FractionsAssessment Practice
4 marks~6 minCriterion C
A two-stage water filtration system removes contaminants at each stage. The fraction of contaminants removed by stage one is x+2x and by stage two is x+4x+2, where x>0 represents the initial contaminant level. The combined removal fraction is the product of the two stage fractions.
a
Deduce a simplified expression for the combined removal fraction after both stages. [1]
b
The initial contaminant level is x=4. Calculate the combined removal fraction and interpret what this value means for the filtration system. [2]
c
A filtration engineer claims that this two-stage system is sufficient to meet a safety standard requiring a combined removal fraction greater than 43 for all x>0. Justify whether the engineer's claim is correct. [1]
Solutions
4QuestionAdding and Subtracting with Common DenominatorsAssessment Practice
6 marks~9 minCriterion B
A chemical engineer models the net concentration of a reagent in a reactor using the expression
x−52x2+3+x−55x−1−x−5x2+2
where x is temperature in °C and x=5.
a
Deduce the general rule for adding and subtracting algebraic fractions that share a common denominator Q. [2]
b
Apply your rule to simplify the expression above, showing all working. [3]
c
The reactor operates safely only when the net concentration expression yields a value greater than 30 for integer temperatures in the range 6≤x≤8. Justify whether the reactor operates safely across this entire range. [1]