09/07/2018 10:33 pm
Percentage and CI SI
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In a mixture of 100 l l of milk and water, 25% of mixture is milk. How much water should be added to mixture so that milk become 20% of mixture?
TG Team 10/07/2018 12:28 pm
Hi Nancy ,
Quantity of milk in the mixture = 25 litres
Quantity of water in the mixture = 75 litres
Let x litres of water be added in the mixture so that [25/ ( 100 + x) ] × 100 = 20
x = 25
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11/07/2018 11:06 am
A watermelon contains 85% of water. 30 g of water evaporates from watermelon and now it containsb80%water. What was original weight of watermelon?
TG Team 11/07/2018 11:33 am
Hi Nancy ,
Let the original weight of the watermelon be x gm.
Water : 85 % of x
Solid Pulp : 15 % of x
30 g water evaporates so ,
New weight : (x - 30 )gm
Water : 80 % of ( x - 30) gm
Solid Pulp : 20 % of ( x - 30)
Now , 15 % of x = 20 % of ( x - 30)
x = 120 gm
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11/07/2018 11:56 am
In a college, 65% of students pass their exam in first year. Among tha students who have to repeat the exam in second year, 50% pass on their second attempt. Among the students who have to retake the paper the third time, 70% pass on their third attempt. What % of students had to take the exam more than 3 times
TG Team 11/07/2018 3:32 pm
Hi Nancy!
Let the number of students be x .
65 % pass the exam in their first attempt, so 35% re-take the exam in the 2nd year i.e = 35x/100 = 7x/20
50 % of 7x/20 pass the exam on their 2nd attempt i.e = 7x/40, so 7x/20 take the exam.
70% of 7x/40 pass the exam on their third attempt, so 30 % of 7x /40 take the exam more than 3 times.
30% of 7x/40= [100(21x/400)/x] %= 5.25 % students had to take the exam more than 3 times.
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12/07/2018 11:39 am
After two successive increase, the orice of a property has become 15/8 times the initial value. By how much percent oice was increased for the first timeif second increase was twice as high as first?
TG Team 12/07/2018 1:04 pm
Hi Nancy!
(1+x)(1+2x)= 15/8
=> 2x² + 3x - 7/8 = 0
=>16x² + 24x - 7 = 0
=>x= 1/4= 25%
Nancyjain 13/07/2018 10:18 pm
in an exam, 48% students failed in phy, 32% students in chem, 20% students failed in both the subjects. If no of students who passed in both was 880, how many students appeared in exam?
TG Team 14/07/2018 2:24 pm
100 - (28 + 20 + 12) = 40% passed the exam
40% of Total students = 880
100% = 2200
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13/07/2018 10:25 pm
A machine depriciates in value each year at the rate of 10 % of its previous value. However, every second year there is some maintainence work so that in that year, depreciation is only 5% of its previous value. If at the end of fourth year tha value of machine is 146205 then find the value of machine t the start of first year?
TG Team 14/07/2018 2:12 pm
Hi Nancy!
let the value of the machine at the start of first year was A.
then according to question : A x 90/100 x 95/100 x 90/100 x 95/100 = 146205
A = 146205 x 20/19 x 20/19 x 10/9 x 10/9
A = 200000.
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14/07/2018 3:13 pm
6% of budget of government is spent on education.if government increases its budget by Rs. 3000 crores and allocates the entire amount for education, the share of education jumps to 9 % what is the original government budget ? (is there shortcut for this question without equations)
TG Team 14/07/2018 5:22 pm
6% of the budget + 3000 = 9% of ( budget + 3000)
6% of the budget + 3000 = 9% of budget + 9% of 3000
3% of budget = 2730
Hence , Budget = 2730 x 100/3 = 91000.
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21/07/2018 9:46 pm
ABHISHEK LEELA PANDEY 22/07/2018 1:08 pm
Hi Samyak
Let the volumes of Cups A and B be 'x' and 'y' units respectively
After the replacements
Beaker A has y/10 - x/5 + 30 units of acid
Beaker B has x/5 - y/10 + 12 units of acid
Equating the above two equations, we get
2x - y = 90
x = y = 90 is the answer
Enjoy 🙂
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06/08/2018 11:27 am
Pls give me solution to this
Ans given is B
TG Team 07/08/2018 12:22 pm
Hello Kartikeya,
It is a poorly framed question. 37.6 seems wrong to me.
Kartikeya 07/08/2018 6:07 pm
Sir i got the answer .. they are only considering the students who gave the exam. Thankyou for your reply.
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09/08/2018 2:18 am
Equal number of males and females were asked, "Do you belebel in marriages are made in heaven?" Every person answered in either yes or no. 60% of those who said yes were males and 80% of those who said no were females. What %age of the females said yes?
TG Team 09/08/2018 11:24 am
Hello Richa ,
See the last example here , http://tathagat.mba/average-mixture/
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16/08/2018 9:19 am
TG Team 16/08/2018 10:49 am
Let it be a square of side S.
Area = S²
Side S is increased by 20% so new side = 1.2S
New area = 1.44S
Percentage Increase = 44.
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17/09/2018 4:53 pm
Gopi went to fruit market with a certain amount of money. With this money he can buy either 50 oranges or 40 mangoes. He retains 10% of the money for taxi fare. If he buys 20 mangoes , then the number of oranges he can buy is?
TG Team 17/09/2018 7:11 pm
Hello Nikita ,
Ratio of mangoes to oranges Gopi can buy is => 4 : 5
Originally he can buy 40 mangoes
After 10% of taxi fare he can buy : 40 x 90/100 = 36 mangoes .
He bought 20 mangoes so he has enough money left to buy 36 - 20 = 16 mangoes
So , 5/4 = Number of oranges /16
=> Number of orangess = 20
TG Team 17/09/2018 7:15 pm
Alternate Approach :
Let the amount of money be 1oo
Cost of 1 mango => 100/50 = 2
cost of 1 orange => 100/40 = 2.5
After 10% of taxi fare money left : 90 .
cost of 20 mangoes => 40
Remaining amount : 90 - 40 = 50 .
So he can buy : 50/2.5 = 20 oranges
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18/09/2018 5:22 pm
aniket prajapati 19/09/2018 9:08 am
This post was modified 6 years ago by aniket prajapati
First he will spend 10,000 in purchasing on which he will get 20% cashback which means he get 2000 RS. Nd again he will spend this money(2000) in purchasing nd he will get 20% cashback on 2000 RS. Which is 400 RS. And he will spend this also so total money for which he can buy products =10,000 + 2000 + 400
=12400 (answer)
shivangi 21/09/2018 9:17 pm
First he will spend 10,000 in purchasing on which he will get 20% cashback which means he get 2000 RS. Nd again he will spend this money(2000) in purchasing nd he will get 20% cashback on 2000 RS. Which is 400 RS. And he will spend this also so total money for which he can buy products =10,000 + 2000 + 400
=12400 (answer)
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19/09/2018 12:12 pm
what is the sum of all the natural numbers frim 1-100 that are niether multiples of 2 nor a multiple of 5?
TG Team 19/09/2018 1:46 pm
Hello Shubhra !
Remove all even numbers
we are left with 50 odd numbers: 1 + 3 + 5 + 7 +..... + 99 = 502 = 2500
(Sum of first n odd numbers = n2)
Now remove all odd multiples of 5: (5 + 15 + ....+ 95) = 10 x (95+5)/2 = 500
Required Sum : 2500 - 500 = 2000.
TG Team 19/09/2018 1:49 pm
Alternate Approach :
We can use Eulers Totient Function here ,
Sum of coprimes of N below N is = N x Phi(N)/2
So , 100 x Phi(100)/2 = 50 x 40 = 200.
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13/10/2018 8:41 pm
aniket prajapati 13/10/2018 10:07 pm
there is a rule in investment market they call it 72 rule
you divide the rate into 72 and you get the years in which sum will get double
here reverse of this rule will follow years is given so we divide years into 72 and we will get rate
72/6=12
option (a)
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18/10/2018 11:12 am
