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Question -

Find the two numbers whose A.M. is 25 and GM is 20.



Answer -

Given: A.M = 25, G.M =20.

G.M = √ab

A.M = (a+b)/2

So,

√ab = 20 ……. (1)

(a+b)/2 = 25……. (2)

a + b = 50

a = 50 – b

Putting the value of‘a’ in equation (1), we get,

√[(50-b)b] = 20

50b – b2 =400

b2 –50b + 400 = 0

b2 –40b – 10b + 400 = 0

b(b – 40) – 10(b – 40)= 0

b = 40 or b = 10

If b = 40 then a = 10

If b = 10 then a = 40

The numbers are 10and 40.

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