Final answer:
Rahul invested the sum for a period of 2.5 years.
Step-by-step explanation:
To find the period for which the sum was invested by Rahul, we can use the formula for simple interest: Interest = Principal x Rate x Time. We know the Principal is Rs. 70,000 and the Interest is Rs. 85,925. The Rate is given as 6.5%. So we can substitute these values into the formula and solve for Time:
85,925 = 70,000 x 0.065 x Time
Simplifying the equation gives:
Time = 85,925 / (70,000 x 0.065)
Calculating this gives:
Time = 2.5
Therefore, Rahul invested the sum for a period of 2.5 years.