Colleen and Jimmy have part-time jobs after school. Both have decided that they want to see how much money they can save
in one semester by placing part of their earnings each week into
a savings account. Colleen currently has $120 in her account and
plans to save $18 each week. Jimmy currently has $64 in his savings
account and plans to save $25 each week.
1. Write an equation for Colleen and for Jimmy that
represents the total amount of money, in dollars, in each
of their savings accounts, y, in terms of the number of weeks,
x, that they place money in their respective accounts.

Colleen has $300 and Jimmy has $703

Step-by-step explanation:

x=10 weeks

Based on a 15 week semester, by the end Jimmy will have accumulated in his savings account $49 more than Colleen

Step-by-step explanation:

Jimmy's Equation: Y = $64 + 25x

Colleen's Equation Y = $120 + 18x

X = # Of Weeks

Y = Total Savings Account

If the average semester is 15 weeks long, then you would plug x = 15

Jimmy:

Y = 64 + 25(15)

Y = $439

Colleen:

Y = 120 + 18(15)

Y = $390

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb