Answer:
ΔR = 5 s
Explanation:
The absolute uncertainty or error in an expression is
ΔR = | [tex]\frac{dR}{dB}[/tex] | ΔB + | [tex]\frac{dR}{dA}[/tex] | ΔA
the absolute value guarantees to take the unfavorable case, that is, the maximum error.
We look for the derivatives
[tex]\frac{dR}{dB}[/tex] = 1
[tex]\frac{dR}{dA}[/tex] = -1
we substitute
ΔR = 1 ΔB + 1 ΔA
of the data
ΔB = 3 s
ΔA = 2 s
ΔR = 3 + 2
ΔR = 5 s