Circuit calculation. Typo?

Question

Electronics

In Swaren's book "Electronics. Step by Step" in the editions of 1986, 1991, 2001 there is a task where you need to make calculations for 6 circuits according to Ohm's law. And in one chain, the calculations do not match. If this is a typo, then it should have been corrected in the next edition, but it is unchanged in all editions. Or is it on purpose? Or am I missing something? In Proteus, calculations are also different from book ones.

Answer 1

Yes, it can be seen that in example 5, a voltage of 140V drops on the part of the circuit formed by resistors R2, R3, R4. In this case, the sum of currents in this part of the circuit is 3A.
Based on Ohm's law, the equivalent resistance of this circuit should be 46.(6) ohms.
However, this equivalent resistance cannot be reached, since the resistance of only one branch of R2 is already 40 ohms.
So yes, there is a mistake and no one has noticed it yet.
A good reason to write to the publisher.