🎓 Deeper Dive — Adults

CI is the single most important math concept for your financial future! 💡

A ₹1 lakh FD at 7% CI for 30 years becomes ₹7.6 lakhs. With simple interest? Only ₹3.1 lakhs. That's ₹4.5 lakhs of difference for doing absolutely nothing extra — just choosing the right type of interest.

Rule of 72: Divide 72 by the interest rate to find how many years it takes to double your money. At 12%: money doubles every 6 years. At 6%: every 12 years. Memorise this — it impresses interviewers AND helps you plan investments.

Exam shortcuts (memorise these):

• CI − SI for 2 years = P × (R/100)²
• CI − SI for 3 years = P × (R/100)² × (3 + R/100)

These two formulas appear in virtually every Bank PO exam. They save 2 minutes per question.