Question

甲乙两根木棒插在水池中,两根木棒的和是230cm,甲棒有5分之3露在水面上,乙棒有4分之1露在水面上,水深多少?

Answer 1

水深={[(1-3/5)X230]/[(1-1/4)+(1-3/5)]}X(1-1/4)

={[(2/5)X230]/[(3/4)+(2/5)]}X(3/4)

={[92]/[(15/20)+(8/20)]}X(3/4)

={[92]/[23/20]}X(3/4)

={80}X(3/4)

=60(cm)

或：

水深={[(1-1/4)X230]/[(1-1/4)+(1-3/5)]}X(1-3/5)

={[(3/4)X230]/[(3/4)+(2/5)]}X(2/5)

={[172.5]/[(15/20)+(8/20)]}X(2/5)

={[172.5]/[23/20]}X(2/5)

={150}X(2/5)

=60(cm)

水深60cm