Oe is purchasing a new cell phone plan and is trying to decide between two different options. Plan #1:
$20 per month base fee
$0.10 per minute
Plan #2:
$10 per month base fee
$0.15 per minute

a. Last month, Joe spent 160 minutes talking on the phone. If he expects to talk this much next month, which plan should he go with?

b. Joe decided to go with Plan #1. If his total bill for the next month was $25.40, how many minutes did he spend talking on the phone? Simply write the number