Answer:
6%
Step-by-step explanation:
Interest = Principal x Rate x Time (in years)
30 = 500r
r = 3/50 or 6/100 which is 6%
Well to be honest this question is really easy by what i understand, if you just need any one line to get a total of 21.
Obviously having three or four such lines might become a problem But not for this. You can obviously break down 21 in to three different categories or numbers like 1 7 and 13. And now put 13 in the middle and start from anywhere. You will get 21 along one such line.
