The Nalini word problem

Here is the question: Nalini invested a total of $24,000 in two mutual funds. Her investment in the Equity Fund is $4000 less than three times her investment in the Bond Fund. How much did Nalini invest in the Equity Fund?

Solution: first, assign a letter to each of the unknown quantities. We have two unknown quantities, let's call the Equity Fund 'E' and the Bond Fund 'B'. Now, because we have two unknown quantities, we will need two equation to find them.

First off, her investment is E + B = 24000. That is from the first sentence.

Now,  the tougher second sentence. Recall that the point of an equation is that both sides must be equal. So, we can write

E = 3B - 4000

Go  back to our first equation. Because an equation is...well....an equation, we can substitute
the rearranged second equation for E into the first equation to get

3B - 4000 + B = 24000 ( make sure you get this bit)

so 4B = 28000
so B = 7000

We can get E like this

E + 7000 = 24000, so E = 17000.

Check your work. Go back to the sentence "Her investment in the Equity Fund is $4000 less than three times her investment in the Bond Fund". Three times the Bond Fund would be 3 * 7 = 21000. Take away 4000 to get 21000 - 4000 = 17000. We're done!