Given :
One cell phone company offers a plan that costs $26.99 and includes unlimited night and weekend minutes.
Another company offers a plan that costs $18.99 and charges $0.35 per minute during nights and weekends.
To Find :
For what numbers of night and weekend minutes does the second company's plan cost more than the first company's plan.
Solution :
Let, after n number of nights and weekends second plan is most costly.
So,
Therefore, after 22 night and weekends second plan is most costly.
Hence, this is the required solution.