Final answer:
Kira's call lasted for 25 minutes.
Step-by-step explanation:
To find out how many minutes Kira's call lasted, we need to subtract the remaining balance on her card from the initial value of the card and divide that amount by the cost per minute of the call.
Initial value of card = $30
Remaining balance = $25.50
Cost per minute = $0.18
Minutes of call = (Initial value - Remaining balance) / Cost per minute
Minutes of call = ($30 - $25.50) / $0.18
Minutes of call = $4.50 / $0.18
Minutes of call = 25
Therefore, Kira's call lasted for 25 minutes.