Answer:
Isabelle spent $52.50 more on Erasers than rulers.
Step-by-step explanation:
Step 1
Find the quantity of each stationery bought in fraction
Let us represent the total fraction of what Isabelle bought as: x
1/3x = quantity of pencils bought
5/8 of the remainder = quantity of erasers bought
The remainder = x - 1/3x = 2/3x
5/8 of 2/3x = 5/8 × 2/3x = 5/12x
Hence, 5/12x = quantity of erasers bought
The rest is rulers
1 - (1/3 + 5/12)
1 - (4 + 5/12)
1 - 9/12
1 - 3/4
= 1/4x
Hence, 1/4 = quantity of rulers bought.
Step 2
We find the number of stationeries that Isabelle bought.
The cost of the stationery is
a Pencil: $1.20
an eraser: $1
a ruler: $0.50.
Total amount spent on stationery = 169.50
We have this equation
1.20 × 1/3x + 1 × 5/12x + 0.50 × 1/4x = 169.50
0.4x + 0.4166666667x + 0.125x =
169.50
0.9416666667x = 169.50
x = 169.50 /0.9416666667
x = 179.99999999
Approximately , the number of stationeries that Isabelle bought = x = 180
Step 3
Find the number and the amount spent on each stationery that Isabelle bought
a) i) Quantity of pencils bought = 1/3 x
x = 180
= 1/3 × 180
= 60 pencils
ii) Amount spent on pencils
If 1 pencil = $1.20
60 pencils =
60 × 1.20 = $72
b) i) Quantity of Erasers bought = 5/12x
x = 180
= 5/12 × 180
= 75 pencils
ii) Amount spent on Eraser
If 1 pencil = $1
75 pencils =
75 × 1 = $75
c) i) Quantity of rulers bought = 1/4 x
x = 180
= 1/4 × 180
= 45 pencils
ii) Amount spent on pencils
If 1 pencil = $0.50
45 pencils =
45 × 0.50 = $22.50
Step 4
We were asked to calculate how much more did she spend on erasers than rulers.
In step 3, the amount spent on Erasers = $75
the amount spent on ruler = $22.5
The difference in the amount spent = $75 - $22.5
= $52.5
Therefore, Isabelle spent $52.50 more on Erasers than rulers.
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minutes or about 24 minutes.