BPSC 66th Prelims 27 Dec 2020 Paper

Concept:To solve a pair of linear equations quickly, substitute the given options into the equations to check which pair satisfies both.Explanation:We have two equations: $217x + 131y = 913$ and $131x + 217y = 827$.Instead of solving algebraically, test each option by plugging the values of $x$ and $y$.For option B: $x = 3$, $y = 2$.First equation: $217 \times 3 + 131 \times 2 = 651 + 262 = 913$. Correct.Second equation: $131 \times 3 + 217 \times 2 = 393 + 434 = 827$. Correct.Both equations are satisfied. No other option works.Answer:$x = 3$ and $y = 2$, i.e., option B.