Thread: Simple interest question

A company invests $50000, some into an account paying 5.2% per annum simple interest and the remainder in an account paying 4.5% simple interest per annum. After 2 years the $50000 had grown to $54976. How much went into each account?

What is the formula for this type of question? I worked it out by trial and error, but I know that this isnt the right way.

Thanks

Originally Posted by Local_lunatic

A company invests $50000, some into an account paying 5.2% per annum simple interest and the remainder in an account paying 4.5% simple interest per annum. After 2 years the $50000 had grown to $54976. How much went into each account?

What is the formula for this type of question? I worked it out by trial and error, but I know that this isnt the right way.

Thanks

Recall that Simple Interest = Principle * Rate * Time

The interest gained here is, of course, 54976 - 50000 = 4976

So now we set up our simple interest equations. we have two accounts, so we must have a sum of the two simple interests giving 4976

Thus we have:

so let's say the first account is the one that gives 5.2% interest. And let's say we invest dollars into this account. what do we have remaining? well, dollars, of course.

so our equation becomes:



or

now solve for , that will be the amount you invested into the first account. then subtract that answer from 50000 to find how much you invested into the second account

Originally Posted by Jhevon

Recall that Simple Interest = Principle * Rate * Time

The interest gained here is, of course, 54976 - 50000 = 4976

So now we set up our simple interest equations. we have two accounts, so we must have a sum of the two simple interests giving 4976

Thus we have:

so let's say the first account is the one that gives 5.2% interest. And let's say we invest dollars into this account. what do we have remaining? well, dollars, of course.

so our equation becomes:



or

now solve for , that will be the amount you invested into the first account. then subtract that answer from 50000 to find how much you invested into the second account

That's basically where I managed to get to except that I simplified it down a bit more.



or

How would I go about solving it for x though?

This may help you http://www.mathhelpforum.com/math-he...rest-rate.html .

Originally Posted by Local_lunatic

That's basically where I managed to get to except that I simplified it down a bit more.



or

How would I go about solving it for x though?

your second line profited nothing.

do you know how to expand brackets?





now we expand the brackets for the second term. we take the 0.09 and multiply each term in the brackets one at a time





now add the x's



Can you take it from here?

So from the beginning















Account 1(x) =$34000
Account 2 =$16000


Here's another one.

Junior invests $4000, some into an account paying 6.5%pa simple interest and the remainder into an account paying 5.8%pa simple interest. After 18months the $4000 has grown to $4391.60. How much did Junior put into each account?















Account 1(x) = $3200
Account2 = $800

Have I done these right?

Originally Posted by Local_lunatic

So from the beginning















Account 1(x) =$34000
Account 2 =$16000


Here's another one.

Junior invests $4000, some into an account paying 6.5%pa simple interest and the remainder into an account paying 5.8%pa simple interest. After 18months the $4000 has grown to $4391.60. How much did Junior put into each account?















Account 1(x) = $3200
Account2 = $800

Have I done these right?

it should be

but you're setup looks correct. work out the answer with the corrected RHS

My bad, the question was meant to be $4381.60 instead of $4391.60. Thanks for helping me understand it