Tom and Jerry went to a restaurant for dinner. Tom ordered 2 hamburgers and 1 soft drink, totalling Rs. 70. Jerry ordered 1 hambu…

Question

Tom and Jerry went to a restaurant for dinner. Tom ordered 2 hamburgers and 1 soft drink, totalling Rs. 70. Jerry ordered 1 hamburger and 2 soft drinks, totalling Rs. 50. Then the cost of one hamburger and one soft drink are

1. A. Hamburger – Rs. 10, Soft Drink – Rs. 30
2. B. Hamburger – Rs. 30, Soft Drink – Rs. 10 (Correct answer)
3. C. Hamburger – Rs. 15, Soft Drink – Rs. 25
4. D. Hamburger – Rs. 25, Soft Drink – Rs. 15

Correct Answer

Option B — Hamburger – Rs. 30, Soft Drink – Rs. 10

Detailed Solution & Explanation

The correct answer is Hamburger – Rs. 30, Soft Drink – Rs. 10.

Key Points

• Let H=hamburger price, S=soft drink.
• 2H+S=70 and H+2S=50. Subtracting: H−S=20. Adding to H+2S=50: 2H+S=70. Solving: H=30, S=10.

Additional Information

• Two unknowns need two equations. Here elimination is quickest: subtracting one from the other removes a variable in a single step.
• The alternatives are substitution (express one variable and insert it) and cross-multiplication, all giving the same result.
• Always substitute the answer back into both original equations — that catches sign errors, which are the usual failure here.
• A pair of linear equations has a unique solution when a₁/a₂ ≠ b₁/b₂; it has none, or infinitely many, when the ratios are equal.