11. Carlos put $100 in a savings account at the beginning of the year. At the end of each month, he added $15 to the account. Ana put $400 in her savings account at the beginning of the year. At the end of each month, she took $35 out of her account. Let x represent the number of months which have passed and y represent the amount in each savings account.
a. Write an equation to represent the amount in Carlos' savings account.
b. Write an equation to represent the amount in Ana's savings account.
c. Copy and complete the input-output tables through 8 months.s
d. When will Carlos and Ana have the same amount in their savings accounts? How much will they each have at this time?