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# Word problems

1.) The average of 5 numbers is 36. The first 4 numbers are 17, 23, 50, and 20. Find the 5th number.

a.) Write an algebraic equation for this problem using "x" as the missing number.

b.) Solve the equation for the missing number (x)

2.) If you invest \$1200 at 4% simple interest, how much additional money would you need to invest at 6% simple interest to obtain \$300 in total interest?

a.) write an algebraic equation for this problem using "x" as the amount needed.

b.) Solve the equation for the unknown amount.

#### Solution Preview

1. Let the fifth (missing) number be x. Now the numbers are 17, 23, 50, 20 and x. Their average is given by (17+23+50+20+x)/5. This simplifies to (110+x)/5. We are given that the average of these five numbers as 36. Hence, we equate both these quantities to get (110+x)/5=36. Multiplying by 5 on both ...

#### Solution Summary

This provides examples of writing equations and solving them from word problems.

\$2.19