Option A is the correct answer.
Before trying to solve the question, first lets understand the information mentioned in it.
So the question starts by telling us that On Monday, Elena had a certain amount in her bank account. Then on Tuesday, she increased that amount by m percent and on Wednesday she withdrew n percent of the amount from her Tuesday's closing balance such that after withdrawing she is left with only 50% of the amount that was in her account on Monday. Now the question asks us to find n in terms of m.
Lets try to solve this question by assuming values so that we can easily do our calculations and find the answer.
So lets take Balance in account on Monday to be 200 and m =100%, so as per the information in the question the amount will Elena added on Tuesday will be 200 and Tuesday's closing balance will be 400 and as per the question the percentage of amount which she withdrew from her account will be 75% respectively.
Lets understand how we get the value of n to be 75%
On Monday Elena's bank balance = 200
Then she added 100% of this amount on Tuesday i.e. 200, So Elena's bank balance on Tuesday = 200+200 => 400
Then she withdrew n percent of amount such that only 50% of the balance which she had on Monday was left i.e. 100 => 400*(n/100) = 300 => n = 75%
Now after understanding how we get to out values
lets try to put them in the given options and see check option gets us the required answer i.e. n = 75%.Option A: (100(m+50))/(m+100) => (100*(100+50))/(100+100) => (100*150)/200 => 75%. This option gets us our desired value so this must be our answer. But lets check other option as well to properly conclude this option as our answer.
SelectedOption B: (100*(m-50))/(m+100) => (100*(100-50))/(100+100) => (100*50)/200 => n = 25%. This option does not gives us n = 75% so
Eliminated.Option C: (100*(m+50))/(100-m) => (100*(100+50))/(100-100) from here only we can tell that the denominator for this will be '0' which can never gives us our desired answer.
EliminatedOption D: 100m/(m+100) => 100*100/(100+100) => n = 50%. This option does not gives us n = 75% so
Eliminated.Option E: (100*(50-m))/(m-100) => (100(50-100))/(100-100) from here only we can tell that the denominator for this will be '0' as well as the numerator will also be in negative which can never gives us our desired answer.
EliminatedSo after checking and solving all the option now we can properly conclude that only Option A gives us the desired value of n i.e. 75% that's why Option A is our answer.Bunuel
On Monday, Elena had a certain amount of money in her savings account. On Tuesday, she increased that amount by
m percent. On Wednesday, she withdrew
n percent of her Tuesday's closing balance, leaving her with exactly 50 percent of what she had on Monday. What is the value of
n in terms of
m?
A. \(\frac{100(m + 50)}{m + 100}\)
B. \( \frac{100(m - 50)}{m + 100}\)
C. \( \frac{100(m + 50)}{100 - m}\)
D. \( \frac{100m}{m + 100}\)
E. \( \frac{100(50 - m)}{m - 100}\)