You need the compound interest formula solved for time:
Years = log (total / principal) / n * log (1 + rate / n)
Years = log (9,000 / 5,960.32) / 2 * log (1 + .042/2)
Years = log (
<span>
<span>
<span>
1.509986041</span></span></span>) / 2 * log (1.021)
Years = 0.1789729325 / 2 * 0.0090257420869
Years =
<span>
<span>
</span></span><span><span><span>0.1789729325 / 0.0180514842
</span>
</span>
</span>
<span><span><span>Years =
9.9145826746
</span>
</span>
</span>
the answer is "d"
Source:
http://www.1728.org/compint.htm
The answer is A. :). Have a great day!
(25/20 -1)*100% = 25%
From 20 to 25 is an increase of 25%.