In a class, there are (74) students. Three times the number of boys plus twice the number of girls is (186). What is the number of girls?
Answer and explanation
Correct answer: 36
Let the number of boys be \(x\) and the number of girls be \(y\). Then \(x+y=74\) and \(3x+2y=186\). Multiplying the first equation by 2 gives \(2x+2y=148\). Subtracting this from the second equation gives \(x=38\). Hence, \(y=74-38=36\). Therefore, the correct answer is 36. Option 38 is the number of boys, not girls. Exam tip: In such questions, multiply the total-number equation suitably to eliminate one variable quickly.
Frequently asked questions
What is the correct answer to this question?
36
Why is this the correct answer?
Let the number of boys be \(x\) and the number of girls be \(y\). Then \(x+y=74\) and \(3x+2y=186\). Multiplying the first equation by 2 gives \(2x+2y=148\). Subtracting this from the second equation gives \(x=38\). Hence, \(y=74-38=36\). Therefore, the correct answer is 36. Option 38 is the number of boys, not girls. Exam tip: In such questions, multiply the total-number equation suitably to eliminate one variable quickly.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Pair of Linear Equations in Two Variables. Topic: Algebraic methods: Substitution method and Elimination method..
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