Need Help PLZ!!!!!!!!!

Answer:
t = 0.93 years
Step-by-step explanation:
Simple interest: I = prt
Given:
Interest(I)= $900, Investment(p) = $21,000, Rate(r) = 4.6% = 0.046
900 = 21000 × 0.046 × t
900 = 966 × t
[tex]\frac{900}{966}[/tex] = t
t = 0.93 years