Percentage Word Problems

PERCENTAGE WORD PROBLEMS

Problem 1 :

The production of rice increased by 50% from 1995 to 1996.By what percentage should the production of rice be increased from 1996 to 1997, so that the production of rice in 1997 becomes six times that of 1995 ?

Solution :

Let the production of rice be 100 tons in 1995.

1995 ===> 100 tons

Because the production has been increased by 50% in 1996 from 1995, we have

1996 ===> 150 toms

Because the production in 1997 becomes six times that of 1995, we have

1997 ===> 600 tons

When we look in to the above calculations, it is very clear that the production of rice has been increased by 450 tons 1997 from 1996.

Percentage increase 1997 from 1996 is

= (450/150) ⋅ 100 %

= 300%

Hence percentage of rice production increased from 1996 to 1997 is 300%.

Problem 2 :

15% of income of A is equal to 25% of income of B and 10% of income of B is equal to 30% of income of C. If income of C is $ 1600, find the total income of A, B and C.

Solution :

Let A,B and C be the incomes of A,B and C respectively

From the given information, we have C = $1600

10% of B = 30% of C

(10/100) ⋅ B = (30/100) ⋅ 1600

B = $4800

So, the income of B is $4800.

15% of A = 25% of B

(3/20) ⋅ A = (1/4) ⋅ 4800

A = (20/3) ⋅ (1/4) ⋅ 4800

A = $8000

So, the income of B is $8000.

A + B + C = 8000 + 4800 + 1600

A + B + C = 14400

Hence, the total income of A,B and C is $14400

Problem 3 :

The length of a rectangle is increased by 50%. By what percent would the width have to be decreased to maintain the same area ?

Solution :

Let the length and width of the rectangle be 100 cm each.

Area of the rectangle = l ⋅ W = 100 ⋅ 100 = 10000 cm²

Given : The length of the rectangle is increased by 50%.

Let the width of the rectangle be decreased by P% to maintain the same area.

After changes,

length = 150

width = (100 - P)% of 100 = 100 - P

Even after the above two changes, area will be same

150 ⋅ (100 - P) = 10000

15000 - 150P = 10000

150P = 5000

P = 33.33%

Hence, the width has to be decreased by 33.33% to maintain the same area.

Problem 4 :

The production of wheat was increased by 20% from the year 1994 to 1995. It was further increased by 25% from 1995 to 1996. Find the the percentage change in the production of wheat from 1994 to 1996.

Solution :

Let the production of rice be 100 tons in 1994.

1994 ===> 100 tons

Because the production has been increased by 20% in 1994 to 1995, we have

1995 ===> 120 toms

Because the production has been increased by 25% in 1996 from 1995, we have

1996 ===> (100 + 25)% of 120

1996 ===> 125% ⋅ 120

1996 ===> 1.25 ⋅ 120

1996 ===> 150 tons

When we look in to the above calculations, it is very clear that the production of rice has been increased by 50% in 1996 from 1994.

Problem 5 :

The price of a table is $ 400 more than that of a chair. If 4 tables and 6 chairs together cost $3600, by what percentage is the price of the chair less than that of the table ?

Solution :

Let "x" be the price of a chair.

Then the price of a table = x + 400.

4 tables + 6 chairs = 3600

4(x + 400) + 6x = 3600

4x + 1600 + 6x = 3600

10x = 2000

x = 200

So, the price of a chair is $400 and the price of a table is $800.

Price of a chair is $400 less than that of the table

Percentage change = (400/800) ⋅ 100% = 50%

Hence, the price of a chair is 50% less than that of the table.