The 10 V is applied across each of the resistors.
For R1: I1 = V / R1 = 10 / 250 = 0.04 A

 For R2: I2 = V / R2 = 10 / 3330 = 0.0030 A

 There are 2 ways to determine the third and last current:

 1. As before For R3: I3 = V / R3 = 10 / 147 = 0.068 A
Notice, as required: 0.04 + 0.0030 + 0.068 = 0.111 A

 2. Knowing that the total current must be 0.111 A then
I3 = 0.111 - I1 - I2 = 0.111 - 0.04 - 0.0030 = 0.068 A as in 1.

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