Aliena invested $2500 in a credit union for 18 months earning 6% p.a. simple interest. How much interest should she have accrued?

6% = 6/100 = 0.06

2500 x 0.06 = 150 interest per p.a (12 months)

150/12 = 12.5 interest per month.

18 months so interest accrued = 18 months x 12.5 interest per month

                                             = $225

I=Prt

P=2500

r=0.06

t=1.5

You can finish it :)