Interest Word Problems

Sam invested 11000 in an acct that pays 11% apr. How much additional money must be invested in an acct that pays an apr of 14% so that the total interest is equal to the interest on the two investments at the rate of 12%?

Comments for Interest Word Problems

Average Rating starstarstarstarstar

Click here to add your own comments

Nov 05, 2010
Rating
starstarstarstarstar
Interest Word Problems
by: Karin

This is a great problem!

Let's write the numerical equation step by step from the problem.

Let x = the amount of additional money needed.

Sam invested 11000 in an acct that pays 11% apr. (11000 * .11)

How much additional money must be invested in an acct that pays an apr of 14%
+.14x

so that the total interest is equal

=

to the interest on the two investments at the rate of 12%

.12(11000 +x)

Now let's put it all together.

11000(.11) + .14x = .12(11000 +x)

Step 1: Compute 11000*.11 and use the distributive property.

1210 + .14x = 1320 +.12x

Step 2: Get the variables on the left hand side by subtracting .12x from both sides.

1210 + 14x - .12x = 1320 + 12.x - .12x

1210 +.02x = 1320

Step 3: Get the constants on the right hand side by subtracting 1210 from both sides.

1210 - 1210 + .02x = 1320 - 1210

.02x = 110

Step 4: Divide both sides by .02

.02x/.02 = 110/.02

x = 5500

The addition amount should be 5500.

Let's check:

11000(.11) + .14(5500) = .12(11000+5500)
1980 = 1980

The interest is equal for both investments.

Hope this helps.

Karin

Click here to add your own comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Students.

Need More Help With Your Algebra Studies?

Get access to hundreds of video examples and practice problems with your subscription! 

Click here for more information on our affordable subscription options.

Not ready to subscribe?  Register for our FREE Pre-Algebra Refresher course.