Question

Find the resistances of two resistors connected in parallel where, One resistor is three times as large as the other. The total resistance is 12 ohms.

Answer 1

1/3x + 1/x = 1/12
=> (1+3)/3x =1/12
=> 4/12x =1/12
=> x = 4

Resistances are 4 ohm and 12 ohm

Answer 2

Hey friend

let the larger resistor be x and small resistor be 3x

R equivalent in parallel combination
=>r eq.=1/r¹+1/r²

Now
=> 12=1/3x+1/x
=>12=4/3x
=>36x=4
=>x=9

So large resistor =9ohm
small resistor= 3ohm