$4.$ Customer Lifetime Value $($LTV$)$

Assuming that the average customer will use their smart phones until they are $85$ years old, how would you calculate the lifetime value for each of the following customers? Assume that their average monthly smart phone cost will remain the same throughout their lives.

Customer Current Age Monthly Cost

Shelly $25$ $$80$

Bruce $16$ $$75$

Khalid $45$ $$25$

Nathan $21$ $$62$

Chloe $32$ $$20$

Brenda $29$ $$30$

Dave $67$ $$50$