Answer: the sum invested = $600
Step-by-step explanation:
Interest (I) = Principal (P) × rate (r) × time (t)
Original amount: I = P × r × 3
Increased by 1%: I + 18 = P × (1+ .01)r × 3
Substitute I with Prt and set the equations equal to each other to find r:
3Pr + 18 = 3.03Pr
Solve for Pr:
18 = 0.03Pr
÷0.03 ÷ 0.03
600 = Pr
