- A₹3.50
- B₹175
- C₹245
- D₹350
Step-by-Step Solution
Let the fixed charge be and the rate per unit and . Subtract: → , then . Check: ✓. ₹3.50 is the per-unit rate, and ₹245 is just the difference between the two bills.
Answer: B) ₹175
A household's monthly electricity bill is a fixed line charge plus a rate for every unit consumed. In June the family used 250 units and paid ₹1050; in July they used 320 units and paid ₹1295. Find the fixed line charge (in ₹).
Class 10Pair of Linear Equations in Two VariablesAlgebra — Systems of Equations
Key idea: Word problems and translation
Most Class 10 questions on this topic are word problems. The skill is in TRANSLATION:
1. Identify the two unknowns; assign variables (e.g., let = age of A, = age of B).
2. Write two equations from the two given pieces of information.
3. Solve by your preferred method.
**Common types**:
- **Age problems**: 'Father is twice as old as son. Five years ago father was three times. Find ages.'
- **Number problems**: 'A two-digit number plus its reverse is 99...'
- **Distance/time/speed**: 'Boat in still water speeds, downstream/upstream rates...'
- **Cost problems**: 'Cost of pencils and pens.'
- **Fraction problems**: 'A fraction becomes 1/2 when 1 is added to numerator and 2 is subtracted from denominator...'
Always CHECK by substituting solution back into the original word problem (not just the equations).
1. Identify the two unknowns; assign variables (e.g., let = age of A, = age of B).
2. Write two equations from the two given pieces of information.
3. Solve by your preferred method.
**Common types**:
- **Age problems**: 'Father is twice as old as son. Five years ago father was three times. Find ages.'
- **Number problems**: 'A two-digit number plus its reverse is 99...'
- **Distance/time/speed**: 'Boat in still water speeds, downstream/upstream rates...'
- **Cost problems**: 'Cost of pencils and pens.'
- **Fraction problems**: 'A fraction becomes 1/2 when 1 is added to numerator and 2 is subtracted from denominator...'
Always CHECK by substituting solution back into the original word problem (not just the equations).
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Practice 5 Similar Questions Free →All Pair of Linear Equations in Two Variables practice questions
More Class 10 Pair of Linear Equations in Two Variables practice
The two lines drawn for a pair of equations are found to have the SAME slope but…Four years from now, Harish will be twice as old as his daughter. Four years ago, he was…If 47x + 31y = 63 and 31x + 47y = 15, find x + y.Solve by substitution: x + 2y = −1 and 2x − 3y = 12. Find x.With 1/x = p and 1/y = q, the pair 3/x + 2/y = 12 and 2/x + 3/y = 13 becomes 3p + 2q =…