Final answer:
Janet's savings will be worth $B. 230,702.57 at the end of 35 years with an interest rate of 4.2 percent.
Step-by-step explanation:
To calculate the worth of Janet's savings after 35 years with an interest rate of 4.2 percent, we can use the formula for compound interest.
The formula for compound interest is:

Where:
A = the future value of the investment/loan, including interest
P = the principal investment amount (the initial deposit)
r = annual interest rate (as a decimal)
n = number of times that interest is compounded per year
t = number of years the money is invested/borrowed for
In this case, Janet saves $3,000 a year, so P = $3,000.
The interest rate is 4.2%, so r = 0.042. The investment is made annually, so n = 1. And she saves for 35 years, so t = 35.
Plugging these values into the formula, we get:

A = $230,702.57