Answer: 30.4%
Step-by-step explanation:
The effective rate enables us see the rate of interest that is actually in operation due to being compounded over a certain period of time.
Effective rate can be calculated by the formula:
= (1 + annual rate) ^ (1 / number of compounding periods) - 1
= ( 1 + 70%)¹/² - 1
= 0.303840
= 30.4%
Compounding period is 2 as this is semi-annual.