Difficulty: Medium
Correct Answer: 40
Explanation:
Introduction / Context:
This marks-allocation problem uses two relationships: a direct multiple between Mathematics and English, and a ratio between Mathematics and History. We then apply the total-sum constraint to solve for each subject’s marks.
Given Data / Assumptions:
Concept / Approach:
Let English = x ⇒ Maths = 3x. From Maths : History = 4 : 3, History = (3/4)*Maths = (3/4)*3x = 9x/4. Sum the three expressions and set equal to 250, then solve for x.
Step-by-Step Solution:
Let E = x, M = 3x, H = 9x/4. Total: x + 3x + 9x/4 = 250. Combine: (4x + 12x + 9x)/4 = 25x/4 = 250. 25x = 1000 ⇒ x = 40. English = 40.
Verification / Alternative check:
Maths = 120; History = 90. Sum = 40 + 120 + 90 = 250, consistent.
Why Other Options Are Wrong:
120 and 90 correspond to Maths and History, not English. 80 is not consistent with the given relationships.
Common Pitfalls:
Mixing up which subject is a multiple of which, or misapplying the 4 : 3 ratio. Always define variables clearly and substitute carefully.
Final Answer:
40
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