Explanation:

Let the number to be multiplied is ‘x’
So the Original Result = 5/3 * x
Result Found = 3/5 * x
Ratio of these two is given as:-
5/3 * x : 3/5 * x
i.e 25 : 9
%age error = (error/original result) * 100% = (25 - 9)/25 * 100%
= 16/25 *100% = 64%