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If two resistances are connected in series, then its equivalent resistance is 45 Ω and if the same resistances are connected in parallel, then its equivalent resistance is 10 Ω, What are the values of these resistances ?

If two resistances are connected in series, then its equivalent resistance is 45 Ω and if the same resistances are connected in parallel, then its equivalent resistance is 10 Ω, What are the values of these resistances ? Correct Answer 15 <span style="">Ω</span>, 30 <span style="">Ω</span>

The correct answer is 15 Ω, 30 Ω.

Key PointsSolution:

R1+R2 =45 ——————(1)

R1R2/R1+R2 =10

R1R2/45= 10

R1R2 = 450 ————(2)

R1= 450/R2

Putting value in eq(1)

450/R2 + R2 = 45

450+R2^2 = 45R2

R2^2 -45 R2 +450=0

R2^2- 30R2–15R2+450=0

R2(R2-30) -15(R2-30) =0

(R2-30) (R2-15) =0

R2= 30 Ohms

R1=15 Ohms

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