What is the value of (a) for (6x+ay=30) and (2x+5y=11) to have no solution?
Answer and explanation
Correct answer: 15
Two linear equations have no solution when \(\frac{a_1}{a_2}=\frac{b_1}{b_2}\ne\frac{c_1}{c_2}\). Here, \(\frac{6}{2}=3\) must equal \(\frac{a}{5}\), so \(\frac{a}{5}=3\) and hence \(a=15\). Also, \(\frac{30}{11}\ne3\), confirming that the two lines are distinct and parallel. Therefore, 15 is correct. Exam tip: equate the ratios of the coefficients first, then verify that the ratio of constants is different.
Frequently asked questions
What is the correct answer to this question?
15
Why is this the correct answer?
Two linear equations have no solution when \(\frac{a_1}{a_2}=\frac{b_1}{b_2}\ne\frac{c_1}{c_2}\). Here, \(\frac{6}{2}=3\) must equal \(\frac{a}{5}\), so \(\frac{a}{5}=3\) and hence \(a=15\). Also, \(\frac{30}{11}\ne3\), confirming that the two lines are distinct and parallel. Therefore, 15 is correct. Exam tip: equate the ratios of the coefficients first, then verify that the ratio of constants is different.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Pair of Linear Equations in Two Variables. Topic: Conditions for solvability.
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