NDA2011MathematicsSequences and SeriesActual
If the arithmetic and geometric means of two numbers are 10,8 respectively, then one number exceeds the other number by
Options
- A8
- B10
- C12
- D16
Correct answer
C. 12
Step-by-step solution
Let numbers are a and b A M = a+b 2 10= a+b 2 a+b=20 ...(i) G . M = a b 8= a b a b=64 (a-b)^2=(a+b)^2-4 a b aligned & =(20)^2-4(64) & =400-256=144 aligned a-b=12 ...(ii) from (i) and (ii) . array rl a+b & =20 a-b & =12 array ] a=16, b=4 16-4=12 one number exceeds the other number by 12 .