Finding maximal total current for a system

1. The problem statement, all variables and given/known data

a) There are two fuses connected in parallel: fuse A has resistance R_A = 1Ω and
maximal current (by which it melts) I_Amax = 1A; fuse B
has resistance R_B = 2Ω and maximal current (by which it
melts) IBmax = 1.2A. What is the maximal total current for
such a system of fuses?

b) What is the total current when the
fuse B is substituted with a fuse C which has R_C = 2Ω and
I_Cmax = 1.7A?

3. The attempt at a solution

for part (a) we have:

[tex] R_B/R_A = I_A/I_B = 2 [/tex] because of that fuse A will melt first (the current through it will be 1 A) so we substitute it in the equation and solve for I_B, we get:

[tex] I_B = 0.5 A [/tex]


[tex] I = 0.5+1 = 1.5 A [/tex]

I’m not sure how to do part B

Edit: Answers are: a) 1.5 A
b) 1.7 A

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