&KDSWHU
- SinceFPrepresents $680, relabel the diagram as
shown below.
From this diagram, you can see that 2P$680 $4000.
Now solve for P.
2 P$680 $4000
2 P$680 $680$4000 $680 Subtract $680 from both sides.
2 P$3320 Simplify.
Divide both sides by 2.
P$1660 Simplify.
So Phil contributed $1660, and Fred contributed the remaining
$4000 $1660, or $2340.
Method 2:Guess and Test
The problem tells us that Fred contributed $680 more than Phil.
You can guess how much Phil contributed and then add $680
to your guess to get the corresponding amount for Fred.
Add the two amounts to see if the total is $4000.
If not, adjust your guess and try again.
Keep track of your guesses in a table.
The amount Phil contributed must be more than $1000
because $1000 $1680 is clearly less than $4000.
Also, it must be less than $2000 because $2000 $2680 is clearly
more than $4000. You might try $1500 as a first guess and then
go on from there.
Phil contributed $1660, and Fred contributed $2340.
Check to make sure your answer makes sense.
Do the two amounts total $4000?
Yes, $1660 $2340 $4000✓
Is Fred’s amount $680 more than Phil’s?
Yes, $2340 $1660 $680✓
$3320
2
2 P
2
Phil’s Amount Fred’s Amount Total Comment
$1500 $2180 $3680 Not enough
$1700 $2380 $4080 Too much
$1650 $2330 $3980 Not enough, but close
$1660 $2340 $4000 Correct!
PP
$4000
$680
3UDFWLFH $FWLYLWLHV
Lesson 14-11 for exercise sets.
