Find the average rate of interest? pls?

Question

A' has $80,000. He lends $40,000 to B, and receives as interest $ 4,000 half-yearly. He lends $ 20,000 to C, and receives as interest $ 1200 quarterly. The rest of his money he lends to D at 23% p.a. Find the average rate of interest A' makes on his capital. Goodluck!

Answer 1

B: 4,000 / 40,000 = 10% half yearly simple interest or 20% yearly which would be 8,000 for year
C: 1,200 / 20,000 = 6% quarterly therefore 24% yearly yielding 4,800
D: 80,000 - B - C = 20,000 * 23% = 4,600

Now add the yearly yields together and divide by original investment
(4,600 + 4,800 + 8,000) / 80,000 = 21.75%

Answer 2

Basically, A shells out 80k and gets back 1200, 5200, 1200, 89800 for quarters 1-4.

I get an IRR of 21%.