Ask Question
20 December, 12:26

Currently, you have $60 and your sister has $135. You decide to save $5 of your allowance each week, while your sister decides to spend her whole allowance plus $10 each week. How long will it be before you have as much money as your sister?

+3
Answers (1)
  1. 20 December, 12:36
    0
    It will take 5 weeks for both to have the same amount of savings.

    It takes a lot longer to explain what is going on than to do the actual maths with shortcuts.

    Explanation:

    Let the count of weeks be

    w

    You start off with $60 in your savings

    This is increased by $5 each week so the total in your savings at any given count of weeks count is:

    $

    60

    +

    $

    5

    w

    ... Equation (1)

    ...

    Your sister does not add to her savings but reduces it by $10 each week. So her savings at any given week count is:

    $

    135

    -

    $

    10

    w

    ... Equation (2)

    ...

    The count of weeks when both savings are equal is defined by the model:

    Equation (1) = Equation (2)

    60

    +

    5

    w

    =

    135

    -

    10

    w



    in dollars

    Add

    10

    w

    to both sides

    60

    +

    5

    w

    +

    10

    w

    =

    135

    Subtract 60 from both sides

    5

    w

    +

    10

    w

    =

    135

    -

    60

    Simplify

    15

    w

    =

    75

    Divide both sides by 15

    Did you know you can treat units of measurement ($) the same way you do the numbers.

    w

    =

    $

    75

    $

    15



    .

    75

    15

    $

    $

    The $ signs cancel out so you are only left with numbers

    w

    =

    75

    15



    75

    :

    15

    15

    :

    15

    =

    5

    1

    =

    5

    w

    =

    5
Know the Answer?
Not Sure About the Answer?
Find an answer to your question 👍 “Currently, you have $60 and your sister has $135. You decide to save $5 of your allowance each week, while your sister decides to spend her ...” in 📗 Mathematics if the answers seem to be not correct or there’s no answer. Try a smart search to find answers to similar questions.
Search for Other Answers