1. **Stating the problem:** A man invested a certain amount at 5% per annum interest. After 1 year, the total amount in the bank is 840000 cedis. We need to find the principal (the amount he initially invested). 2. **Formula used:** The total amount $A$ after 1 year with simple interest is given by: $$A = P + P \times r \times t = P(1 + rt)$$ where $P$ is the principal, $r$ is the rate of interest per annum (in decimal), and $t$ is the time in years. 3. **Given values:** - $A = 840000$ - $r = 5\% = 0.05$ - $t = 1$ year 4. **Substitute the values into the formula:** $$840000 = P(1 + 0.05 \times 1) = P(1 + 0.05) = P(1.05)$$ 5. **Solve for $P$:** $$P = \frac{840000}{1.05}$$ 6. **Calculate:** $$P = 800000$$ **Answer:** The man invested 800000 cedis.