Accumulated value over eighteen months

Statement

Find the accumulated value of a capital of $3000\ \text{€}$ invested for $18$ months at $10\%$ simple interest.

Solution

The time is $t = \dfrac{18}{12} = 1{.}5$ years. With $M = C\,(1 + r\,t)$: $M = 3000\,(1 + 0{.}10\cdot 1{.}5) = 3000\cdot 1{.}15 = \boxed{3450\ \text{€}}.$