GIVEN: Simple interest for 10 years = Rs. 800
Principal is tripled after 5 years
Concept Used: Simple Interest
= Simple Interest ∝ Time
Simple Interest ∝ Principal
Simple Interest ∝ Rate
CALCULATION: Simple interest for 10 years = Rs. 800
So, Simple interest for first 5 years = Rs. 400 ----(1)
According to the question,
If the principal is tripled after 5 years
Then according to the concept used
Simple interest for rest of 5 years will also be tripled
So, Simple interest for rest 5 years = 400 × 3 = Rs. 1200
∴ Total interest for 10 years = 1200 + 400 = Rs. 1600