Difficulty in the two of the four questions online quick test Chapter 5 IAS 23

I got question 1 and 3 wrong. I followed the method of calculating weighed average as demonstrated in the lecture. For question 1 I got weighted average 9.77% and add 9.77%*9/12*6 M and 9.77%*5/12*2 M. For question 3 I got weighted average 11.6% and add 8/12*60M*11.6% and 2/12*20M*11.6%. Please help me out. Thanks