Problem K. 794. (January 2024)

K. 794. We have invested \(\displaystyle 10\,0000\) Euros for one year, 4000 Euros of which for an interest rate of \(\displaystyle 5\%\) per year, and 3500 Euros of which for an interest rate of \(\displaystyle 4\%\) per year. Find the interest rate for the remaining sum, if the total profit of our investment is 500 Euros.

(5 pont)

Deadline expired on February 12, 2024.

Sorry, the solution is available only in Hungarian. Google translation

Megoldás. \(\displaystyle 4000\cdot0,05+3500\cdot0,04=340\), azaz kell még \(\displaystyle 160 = 2500 \cdot p\), ahonnan \(\displaystyle p = 0,064\), tehát 6,4%-os kamatra kell a maradékot lekötni.

Statistics:

137 students sent a solution.
5 points:	55 students.
4 points:	18 students.
3 points:	2 students.
2 points:	1 student.
Not shown because of missing birth date or parental permission:	61 solutions.

Problems in Mathematics of KöMaL, January 2024