Here, Simple Interest (I) = ₹ 840
Rate (r) = 5.25%
Time (t) = 2 years
Principal (P) =\frac{\text { Interest } \times 100}{\text { Rate } \times \text { Time }} \\
=\text { ₹ } \frac{840 \times 100}{5.25 \times 2}=\text { ₹ } \frac{840 \times 100 \times 100}{525 \times 2} \\
= ₹ 40 × 200 = ₹ 8000
∴ She deposited ₹ 8000