Mary decided to save a certain amount of her monthly salary each month

Question

Mary decided to save a certain amount of her monthly salary each month and her salary was unchanged from month to month. If Mary's savings by the end of the year from these monthly savings were three times the amount she spent per month, what should be the fraction of her salary that she spent each month?

(A) 1/2
(B) 2/3
(C) 1/4
(D) 4/5
(E) 5/6

(A) 1/2
(B) 2/3
(C) 1/4
(D) 4/5
(E) 5/6

Skywalker18 · Accepted Answer

Let Mary's monthly savings = S
Mary's monthly pay = P
Mary's monthly expenditure = P-S

Mary's savings by the end of the year from these monthly savings were three times the amount she spent per month
12S = 3*(P-S)
=>4S = P-S
=> P = 5S

Mary's monthly expenditure = P-S = 5S-S = 4S

fraction of her salary that Mary spent each month = 4S / 5S = 4/5
Answer D

chetan2u · Answer

Hi,

Let the salary per month be y and expenditure be x.. 
If Mary's savings by the end of the year from these monthly savings were three times the amount she spent per month, --  3(y-x) = 12x........y-x=4x......y=5x

fraction of salary spent =  \frac{y-x}{y} = \frac{5x-x}{5x} =\frac{4x}{5x}= \frac{4}{5} ..
D

Abhishek009 · Answer

Capture.PNG Or, 12i - 12e = 3e Or, 12i = 15e Or, 5e = 4i Or, e = 4i/5 Hence the correct answer will be (D)

Nightfury14 · Answer

Saving = S, Expenditure = E, Income = I
At the end of 12months; 12S=3E=3(I-E)
=> 15S = 3I => Savings = 1/5
Hence Expenditure = 1-(1/5) = 4/5  Answer (D) 
__________________________________________________________

A simpler way which helped me solve the problem in 15 sec.
 Analyze the ans needs to be in the form = Expenditure / Income 
Hence    
So ..
(A) 1/2 => 3 x (1) = 12 x (2-1) ... Incorrect
(B) 2/3 => 3 x (2) = 12 x (3-2) ... Incorrect
(C) 1/4 => 3 x (1) = 12 x (4-1) ... Incorrect
 (D) 4/5 => 3 x (4) = 12 x (5-4) ... Correct 
(E) 5/6 => 3 x (5) = 12 x (6-5) ... Incorrect

Hope the post helped
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Youraisemeup · Answer

Savg.=Sal.-Spendg.

(here Savg., sal. and spendg. are monthly).

Therefore: 3 spendg. =12 savng.
solving==> 3 spendg.=12 sal. -12 spendg.
15 Spendg=12 Sal.
Spendg=4/5 *sal.

(D)

HolaMaven · Answer

Let assume her monthly salary is 100
Yearly income is 1200
Let she spend x per month. So total expenditure is 12x
Total saving is 3 times monthly expenditure i.e. 3x.
Total income is total savings + total expenditure = 12x+3x = 15x = 1200
so x =  \frac{1200}{15}  = 80
Thus fraction of expenditure per month =  \frac{80}{100}  = \frac{4}{5}

laulau · Answer

Let T be the amount spent and X be the total income. Thus, the amount saved = (X-T). The question asks us to find \(\frac{T}{X}\).

We can set up an equation:

\(12(X-T)=3T\)
\(12X-12T=3T\)
\(12X=15T\)
\(\frac{12}{15}=\frac{X}{T}\)
\(\frac{4}{5}=\frac{T}{X}\)

Please hit Kudos if you liked this approach

ScottTargetTestPrep · Answer

We can let Mary’s monthly savings = n and monthly spending = p.

At the end of the year, her savings was 12n, which was 3 times what she spent per month, and thus:

12n = 3p

4n = p

Thus, the fraction that she spent each month was p/(p + n) = 4n/(4n + n) = 4/5.

Answer: D

Archit3110 · Answer

let salary be 100
expenditure = x
saving ; 100-x
If Mary's savings by the end of the year from these monthly savings were three times the amount she spent per month
i.e
12*(100-x)=3x
solve for x = 80
so fraction of her salary that she spent each month ; 80/100 ; 4/5
IMO D

bumpbot · Answer

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Mary decided to save a certain amount of her monthly salary each month

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