A bat and a ball cost Rs 110 together. The bat costs Rs 100 more than the ball

Why

Ravi's answer is the one that jumps out — 110, take away the 100 difference, 10 left for the ball — and it feels so clean that most people stop there. Check it, though: if the ball is 10 and the bat costs 100 more, the bat is 110, and together they come to 120, not 110. The catch is that raising the ball's price raises the bat's price too, so it moves the total by twice as much. Call the ball's price x: the bat is x plus 100, and x + (x + 100) = 110, so 2x = 10 and x = 5. The ball is Rs 5, the bat is Rs 105, the difference is Rs 100 and the total is Rs 110 — every condition satisfied. Test: notice how the quick answer breaks the total while the checked answer fits both facts. Meena is right, the ball costs Rs 5: the fast guess skips testing itself against both statements, and here the obvious number fails.