
1) Since this is a Continuously Compounded operation in a 10 yrs period, then we can write out the following equation:

2) Plugging into the equation the given data and since Otto is 20 yrs old and he plans to get $4,000 in ten years, we can write out:

3) Thus the rate Otto needs is

Note that since the 0.1386 the six here is greater than 5 then we can round up to the next thousandth, in this case: 0.139. For the 0.1386 is closer to 0.139 (0.004) than to 0.138 (0.006).
Or 13.9%
<span>The right answers would be B (7 miles after marker 58)
and C (7 miles before marker 58). The problem doesn't say if the rest area is going to be built 7 miles before milepost 58 or 7 miles after it.</span>
Your answer would be 4, because the equation for the circumference of a circle is π × diameter, so if you have 4 × π as the circumference, then 4 is the diameter.
I hope this helps!