The length of a rectangle is increased by 10% and breadth
The length of a rectangle is increased by 10% and breadth decreased by 10%. Then the area of the new rectangle is
The length of a rectangle is increased by 10% and breadth decreased by 10%. Then the area of the new rectangle is
Nithin K ? Nov 20 '2016 at 19:16
Answer is : decreased by 1%
Explanation :
Suppose
Length is 10cm.
Breadth is 20cm.
Then old Area = Length x Breadth = \(10 \times 20\) = 200 ......................(i)If Length increased by 10% = 11cm
if Breadth decreased by 10% = 18cm
So, new Area = \(11 \times 18 \)= 198 ..............................(ii)From (i) and (ii)
old area = 200
new area = 198
So new area is decreased by 1%
The ratio of the number of boys and girls in a school is 3 : 2. If 20% of the boys and 30% of the girls are scholarship holders, then the percentage of students, who do not get scholarship, is
Nithin K ? Nov 20 '2016 at 19:15
Answer is : 76
Explanation :
Let the number of boys & girls be 3x and 2x.
Number of those who are not scholarship holders
\(=(\text{80% of 3x} + \text{70% of 2x})\)
\( = \frac{12x}{5} + \frac{7x}{5}\)
\( = \frac{19x}{5}\)
Required Percentage \(= \frac{19x}{5} * \frac{1}{5x} * 100\% = 76%\)
The speeds of A and B are in the ratio 3 : 4. A takes 20 min more than B to reach a destination. In what time does A reach the destination?
Nithin K ? Nov 20 '2016 at 19:6
Answer is : \(1\frac{1}{3} h\)
Ratio of speed = 3:4;
Ratio of time taken = 4:3 (distance remains constant.)
Let time taken by A and B be 4x and 3x hour respectively.Then,
\(4x-3x = \frac{20}{60};\)
\(=> x = \frac{1}{3};\)
Hence, time taken by A = 4x
\(= 4*\frac{1}{3} = 1\frac{1}{3} hours.\)
1 litre of water is added to 5 litre of alcohol - water solution containing 40% alcohol strength. The strength of alcohol in the new solution will be
Nithin K ? Nov 20 '2016 at 19:2
Answer is : \(33 \frac{1}{3}\%\)
Alcohol in the earlier mixture = 40% of 5 liters = 2 liters
Mixture after addition of 1 liter of water = 5 + 1 = 6 liters
Therefore strength of alcohol in the new mixture in percentage = \(\frac{2}{6}*100\)
\(=\frac{100}{3} %\)
\(=33\frac{1}{3}\%\)
If a : b : c = 2 : 3 : 4 and 2a - 3b + 4c = 33, then the value of c is-
Nithin K ? Nov 20 '2016 at 18:52
Answer is : 12
Explanation:
\(a:b:c = 2:3:4\)
\(\therefore \frac{a}{2} = \frac{b}{3} = \frac{c}{4} =k\)
\(=>a=2k, b=3k, c=4k\)
\(\text{Given, } 2a-3b+4c =33\)
\(=> 2 * 2k - 3*3k+4*4k =33\)
\(=> 4k =9k+16k=33\)
\(=>11k =33\)
\(=> k = \frac{33}{11} =3\)
\(\therefore c = 4k \)
\(=> 4*3 =>12\)
The ratio of incomes of A and B is 5 : 6. If A gets Rs.1100 less than B their total income (in rupees) is-
Nithin K ? Nov 20 '2016 at 17:35
Answer is : 12100
Let Their incomes be 5x and 6x
6x - 5x =1100
=>x = 1100So Total Income is
=6x+5x
=11x
=11(1100)
=12100
There are sets of English, Mathematics and Science books containing 336, 240, 96 books respectively have to be stacked in such a way that all the books are stored subject-wise and the height of each stack is the same. Total number of stacks will be-
Nithin K ? Nov 20 '2016 at 17:34
Answer is : 14
First the number of books in each stack is HCF[336, 240,96] = 48
Total number of stacks = \(\frac{336}{48} + \frac{240}{48} +\frac{96}{48} = 14.\)