I found this problem while helping my nephew with his "O" level mathematics. My solution doesn't match the answer. Can anybody point out the error in my procedure?
"A woman buys a house valued at \$18000. She pays 30% of its value immediately, \$6000 eighteen months later and the remainder after a further eighteen months. Simple interest is charged at 4.5% per annum. Find how much she pays altogether?"
My solution 18000+(12600*0.045*1.5)+(6600*0.045*1.5) = 19296 doesnt' match the answer. The answer is given \$19350