explanation: you’re charged $50 for the first 400 minutes that you talk. you spend an additional 50 minutes, every additional minute costs $0.10. because of this, you multiply $0.10 by 50, which is 5. add the initial cost ($50) to the additional fee ($5). 50+5=55
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.
