L1-6: Writing Equations

Objectives: (Do not write)•Students will become familiar with and model word problems•Students will solve algebraic word problems

Solving Word Problems:

a) Name a variable

b) Write an equation

c) Solve (check)

Types of problems:

• Translate

• Percent

• Set amount – per unit amount

partbase%“part” is the amount “affected” by the

% and must match the %

Original (starting) amount

bmxy Change per unit Set amount

Examples: Write an equation and solve.

1) An appliance repair service charges $50.00 per job plus $12.00 per hour. What is the cost of a 3 hour job?

a) Let c=cost and h=hours

b) C = ____ h + _______5012

c) C = 12(3) + 50

C = $86

2) If you invested in a stock at and the value is now .

What percent of the original investment is the value now?

a) Let p=percent

8

326

2

122

partbase%

2

122

8

326 p

%3.85p

b)

c)

ChallengeThe World Record (WR) for 800m run has decreased since

1930 by 1.82min minus 0.0035 times years since 1930. What would be the current (2010) WR time?

How would you find years passed?

a) Let t = time to run and y = # of years

b) t = 1.82 – 0.0035(y)

c) t = 1.82 – 0.0035(80)

t = 1.54 minutes

Extra: Look it up!! Is this true????

Subtract 1930 from current year

Did you know 800 m is ½ mile!!!!