Answer:
0.75 = 75% probability that exactly one tag is lost, given that at least one tag is lost
Step-by-step explanation:
Independent events:
If two events, A and B, are independent, then:

Conditional probability:

In which
P(B|A) is the probability of event B happening, given that A happened.
is the probability of both A and B happening.
P(A) is the probability of A happening.
In this question:
Event A: At least one tag is lost
Event B: Exactly one tag is lost.
Each tag has a 40% = 0.4 probability of being lost.
Probability of at least one tag is lost:
Either no tags are lost, or at least one is. The sum of the probabilities of these events is 1. Then

p is the probability none are lost. Each one has a 60% = 0.6 probability of not being lost, and they are independent. So
p = 0.6*0.6 = 0.36
Then

Intersection:
The intersection between at least one lost(A) and exactly one lost(B) is exactly one lost.
Then
Probability at least one lost:
First lost(0.4 probability) and second not lost(0.6 probability)
Or
First not lost(0.6 probability) and second lost(0.4 probability)
So

Find the probability that exactly one tag is lost, given that at least one tag is lost (write it up to second decimal place).

0.75 = 75% probability that exactly one tag is lost, given that at least one tag is lost