Answer:
The bill is $40
Step-by-step explanation:
The equation to finding it would be 50m (months)=400t (additional talk time). Since there is a $0.10 charge for each extra minute and do that times 50 for 5. You then plug 5 in for t and you multiply 400 and 5 for 2000. Then divide 2000 and 50 so m=40.