What is the value of x?

No offence taken bro! Definitely I screwed enough to raise such doubts on my tips and solutions (remember to sleep well before your exam )

To know where you/marcab went wrong, you need to focus on basic concept of solving linear equations. You MUST be able to eliminate one of the variables. some do it with substitution and some using addition/substraction- whichever is easier in the given context.

For this question: if you are getting a soltion- that is correct. Ans must be C not E for the set of equations.

Responding to a pm:

When you have two distinct linear equations in two variables, you can solve for the two variables. In other words, a linear equation in 2 variables represents a line. When you have two non-parallel distinct lines, you get one unique point of intersection of the two lines. i.e. there is a single value of x and y which satisfies both equations.

It is obvious here that both statements alone are not sufficient.

Taking both together,
x/7 + 5y =109 => x + 35y = 109*7
175y = 763(5 - x) You can see that when you get x on the left hand side, the co-efficient of x (which is 763) is much larger than the co-efficient of y (which is 175). In the first equation, the coefficient of x (which is 1) is smaller than the coefficient of y (which is 35). So you cannot reduce the equation in a way that the ratio of co-efficients of x will be equal to ratio of co-efficients of y. Hence there will be a unique solution. Answer will be (C)


OE discusses the case where 'the ratio of co-efficients of x will be equal to ratio of co-efficients of y'. One of the two equations have been given incorrectly in the question.

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