Explanation:
1.
1% of 500 is 5 so multiply 5 by 8 for one year. which is 40 so multiply that by 2.
1% of 500 = 5
5 × 8 = 40
40 × 2 = 80
2.
1% of 1000 = 10
10 × 5 = 50
50 × 3 = 150
3.
12 months = 6%
6/12 = 1 month
0.5 = 1 month
0.5 × 9 = 4.5 (the amount of interest for 9 months.)
800 × 4.5% = 36
4.
12 months = 7%
7/12 = 1 month ( i'll leave this in fraction form because of the decimal points.)
7/12 x 8 = 4.666667 or 4.7 rounded.
1200 × 4.7% = 56.40