Remedial math question please help some one?

Question

if you invest 5000 in both a cd and a savings bond, cd makes 4%interest and savings bond7%, accumulates 300.how much was originally invested in the cd account?

Answer 1

The easiest way is to start with a proportion:

4/100 = x/300

To solve the proportion, you would have to make the denominators equal:

4/300 = x/300

But you would also have to change the numerator, the same way you changed the denominator:

12/300 = x/300

That means x = 12!

Not $12, though. 12%.

12% of 5000:

5000 * .12 = 600

Your answer is $600.