Percentage
- A number is increased by 20% and then it is decreased by 10%. Find the net increase or decrease per cent.
-
View Hint View Answer Discuss in Forum
Using Rule 4,
Net % change= 
A + B + AB 
% 100
Here, A = 20%, B = – 10%
∴ Net % change20 - 10 - 200 100
= 10 – 2= 8%
+ ve sign shows increaseCorrect Option: C
Using Rule 4,
Net % change= A + B + AB % 100
Here, A = 20%, B = – 10%
∴ Net % change20 - 10 - 200 100
= 10 – 2= 8%
+ ve sign shows increase
- A man invests a part of 10,000 at 5% and the remainder at 6%. The 5% investment yields annually 76.50 more than the 6% investment . The amount invested at 6% is
-
View Hint View Answer Discuss in Forum
Let the amount invested at 6% = ₹ x
∴ Amount invested at 5%
= (10000 – x )
According to the question(1000 - x) × 5 - x × 5 = 76.50 100 100
⇒ 50000 – 5x – 6x = 7650
⇒ 50000 – 11x = 7650
⇒ 11x = 50000 – 7650 = 42350⇒ x = 42350 = ₹ 3850 11 Correct Option: C
Let the amount invested at 6% = ₹ x
∴ Amount invested at 5%
= (10000 – x )
According to the question(1000 - x) × 5 - x × 5 = 76.50 100 100
⇒ 50000 – 5x – 6x = 7650
⇒ 50000 – 11x = 7650
⇒ 11x = 50000 – 7650 = 42350⇒ x = 42350 = ₹ 3850 11
- Neha’s weight is 140% of Tina’s weight. Mina’s weight is 90% of Lina’s weight. Lina weighs twice as much as Tina. If Neha’s weight is x% of Mina’s weight, then x is equal to :
-
View Hint View Answer Discuss in Forum
Let Tina’s weight = 1 kg
Lina’s weight = 2 kg
Neha’s weight = 1.4kg
Mina’s weight = 1.8 kg.∴ 1.8x = 1.4 100 ⇒ x = 1.4 × 100 = 700 = 77 7 1.8 9 9 Correct Option: B
Let Tina’s weight = 1 kg
Lina’s weight = 2 kg
Neha’s weight = 1.4kg
Mina’s weight = 1.8 kg.∴ 1.8x = 1.4 100 ⇒ x = 1.4 × 100 = 700 = 77 7 1.8 9 9
- The number of seats in a cinema hall is increased by 25%. The cost of each ticket is also increased by 10%. The effect of these changes on the revenue collection will be an increase of
-
View Hint View Answer Discuss in Forum
Let the number of seats initially in the cinema hall be 100 and the cost of each ticket be ₹ 100.
∴ Total revenue = 100 × 100 = ₹ 10000
In second condition,
Number of seats = 125
Cost of each ticket = ₹ 110
∴ New revenue
= 125 × 110 = ₹ 13750
Increase in revenue collection
= ₹. (13750 – 10000) = ₹ 3750
∴ Percentage increase= 3750 × 100 = 37.5% 10000
Aliter : % Increase in revenue= x + y + xy % 100 = 25 + 10 + 25 × 10 % = 37.5% 100 Correct Option: A
Let the number of seats initially in the cinema hall be 100 and the cost of each ticket be ₹ 100.
∴ Total revenue = 100 × 100 = ₹ 10000
In second condition,
Number of seats = 125
Cost of each ticket = ₹ 110
∴ New revenue
= 125 × 110 = ₹ 13750
Increase in revenue collection
= ₹. (13750 – 10000) = ₹ 3750
∴ Percentage increase= 3750 × 100 = 37.5% 10000
Aliter : % Increase in revenue= x + y + xy % 100 = 25 + 10 + 25 × 10 % = 37.5% 100
- A man had a certain amount with him. He spent 20% of that to buy an article and 5% of the remaining on transport. Then he gifted 120. If he is left with 1,400, the amount he spent on transport is
-
View Hint View Answer Discuss in Forum
Total amount = ₹ x
∴ x - x - 4x × 5 - 120 = 1400 5 5 100 ⇒ x - x - x = 1520 5 25 ⇒ 25x - 5x - x = 1520 25 ⇒ 19x = 1520 25 ⇒ x = 1520 × 25 = ₹ 2000 19
∴ Expenditure on transport= 1 × 2000 = ₹ 80 25 Correct Option: D
Total amount = ₹ x
∴ x - x - 4x × 5 - 120 = 1400 5 5 100 ⇒ x - x - x = 1520 5 25 ⇒ 25x - 5x - x = 1520 25 ⇒ 19x = 1520 25 ⇒ x = 1520 × 25 = ₹ 2000 19
∴ Expenditure on transport= 1 × 2000 = ₹ 80 25
