Advanced MathVery hardSum of a number and its reciprocal from a product
Advanced Math practice question
Two positive numbers have a product of 1 and a sum of 13/6. What is the larger of the two numbers?
Answer: 3/2 or 1.5
The numbers are r and 1/r with r + 1/r = 13/6, so 6r² − 13r + 6 = (2r − 3)(3r − 2) = 0 and the larger is 3/2.
Common wrong answers
- If you answered 6
- 6 is the denominator of the sum.
- If you answered 2/3
- 2/3 is the smaller number.
- If you answered 13/6
- 13/6 is the sum.
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