Problem: The sum of two numbers is 101010; their product is 202020. The sum of their reciprocals is:
Answer Choices:
A. 1/101 / 101/10
B. 1/21 / 21/2
C. 111
D. 222
E. 444 Solution:
1x+1y=y+xxy=1020=12\dfrac{1}{x}+\dfrac{1}{y}=\dfrac{y+x}{x y}=\dfrac{10}{20}=\dfrac{1}{2} x1​+y1​=xyy+x​=2010​=21​