$Home$
Workshopmatics $Parents' Course$
$Parents' Seminar$
$2012 Kids' Class$
$2011 Kids' Class$
Forum-matics $PSLE Math Forum$
$Grade 1 Math$
$Grade 2 Math$
$Grade 3 Math$
$Grade 4 Math$
$Grade 5 Math$
$Grade 6 Math$
$Coaching Journals$
$Archive$
Singa-matics $Singapore Math$
$Syllabus$
$Testimonials$
$eZine$
$Kids Math Blog$
$Contact Us$
$About Us$
$Great Math Sites$
$Useful Links$
$Disclaimer$
Concept-matics $Part-Whole$
$Comparison$
$Change$
$Place Holder$
$Remainder$
$Equal$
$Excess Value$
$Repeated Variable$
$Constant Difference$
$Constant Quantity$
$Contant Total$
Model-matics $Addition$
$Subtraction$
$Multiplication$
$Division$
$Comparison$
$Fractions$
$Percentage$
$Decimals$
$Average$
$Ratio$

[?] Subscribe To This Site

$XML RSS$
$Add to Google$
$Add to My Yahoo!$
$Add to My MSN$
$Subscribe with Bloglines$

Questions and Answers

Question posted by Kelvin and Jeanie from Singapore:

Grade/Level: Primary 4

Fred saves $90 more than Tim every mth.
Each of them spends $2000 and saves the rest every month.
When Fred has saved $2600, Tim only saved $1700.

a) how long does it take Tim to save $1700?

b) how much does Tim earn in a month?

Answer:

Step 1: Since both Fred and Tim spent the same amount of money, we draw 2 boxes to represent the $2000 each of them spent.

Step 2: As Fred saved $90 more than Tim every month, we draw a longer box for Fred and a shorter one for Tim to represent the amount of money saved each month. $modelmethodquestionsandanswers122$
Step 3: The above model represents the total spending and savings for the 1st month for both of them. Since this pattern will be repeated month after month, we draw a dotted line to represent the repetition of this behaviour. $modelmethodquestionsandanswers123$
(a)

Difference in Total Savings = $2600 - $1700 = $900

Difference in Monthly Savings = $90

Number of months taken to accumulate the total difference in savings = $900 / $90 = 10 months

Thus, Tim took 10 months to save $1700.

(b)

Since Tim saved $1700 in 10 months

His savings per month = $1700 / 10 months = $170 per month

Thus, his salary = $2000 + $170 = $2170 per month.