P, Q, and R earn Rs. 1620 over 9 days. P and R earn Rs. 600 in 5 days, whereas Q and R earn Rs. 910 in 7 days. What is R's daily earnings?
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Answer: B. Rs.70
Explanation
We determine R's daily earnings by setting up simple algebraic equations based on the combined totals provided. Subtracting the earnings of P and R from the total earnings of P, Q, and R reveals the daily earnings for Q. Subtracting Q and R's earnings from the total gives P's earnings, allowing us to accurately isolate R's final amount. Simultaneous linear equations are fundamental tools used to solve for multiple unknown variables across overlapping conditions. The total earnings divided by the total number of days gives the average combined daily rate of the workers involved. Isolating a single variable requires careful elimination of the other variables through strategic subtraction of equations.
Option A is incorrect because it underestimates the daily rate derived from the primary earnings equations. Option C overestimates the resulting value because it fails to properly account for the overlapping work periods. Option D is wrong as it does not satisfy the combined earnings totals given for the various groups of workers.
- Subject
- Mathematics
- Category
- Mathematics
- Topic
- —
- Difficulty
- medium
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