Mallapragada's Mathematics (7th standard -8)

1.Rama has a road map with a scale of 1cm representing 18km.  She drives on a road for 180km.  What would be her distance covered in the map.

2. In a school x. 72 students  appeared  for 10^th class exam out of which 36 students.  In another school y, 30 students appeared and 24 students passed.  If the D.E.O. wants to give  an award on the basis of pass percentage, to which school will he give the award.

3. Last year the cost of 1000 articles was Rs. 5000.  This year it goes down to 4000.  What is the percentage of decrease in price?

4. Out of 12,000 voters in a constituency, 60% voted.  Find the number of people voted in the constituency.

5. A local cricket team played 20 matches in one season.  If it won 25% of them and lost rest, how many matches did it loose.

6. In every gram of gold, a gold smith mixes 0.25gm of silver and 0.05 of copper .  What is the percentage of gold, silver and copper in every gram of gold.

7.a shopkeeper bought a suitcase for Rs. 480 and sold it for Rs. 540.  Find his gain percent?

8. Rama bought a T.V. for Rs. 15,000 and sold it for Rs. 20,000.  Find the gain percent ?

9. Ramu sold a plot of land for Rs. 2,40,000 gaining 20% For how much did he purchase of the plot.

10. On selling a mobile for Rs. 1000, a shopkeeper loses 10% For what amount should be sell it to gain 5%?

11. a former sold 4 bullocks for Rs. 24,000 each.  On one bullock he gained 25% on the other he lost 30% Find his total profit or loss percent. 

12.Rama bought a watch for Rs. 480.  He sold it to Krishna at a gain of 6 ¼% Krishna sold it to divya at a gain of 10% How much did Divya pay for it?

13.The marked price of a book is Rs. 225.  The publisher allows a discount of 10% on it.  Find the selling price of it.

14. A carpenter allows 15% discount on his goods.  Find the marked price of a chair which is sold by him for Rs. 850

15. a dealer allows a discount of 10% and still gains by 10%. What should be the marked price if the cost price is Rs. 1000

1.Rama has a road map with a scale of 1cm representing 18km.  She drives on a road for 180km.  What would be her distance covered in the map.

Scale of the map is 1 cm.  = 18km., Distance covered 180km.

Let it be x cm map , than  1: 18 :: x : 180

18 x = 180       There fore x = 180/18 = 10 cm.

2. In a school x. 72 students  appeared  for 10^th class exam out of which 36 students.  In another school y, 30 students appeared and 24 students passed.  If the D.E.O. wants to give  an award on the basis of pass percentage, to which school will he give the award.

No.of  students appeared 10^th class = 72

No. of students passed = 36, percentage = 36/72 x 100 = 50%

No. of students appeared = 30, passed students = 24

Pass percentage = 24/30 x 100 = 80% , 80%>50%

3. Last year the cost of 1000 articles was Rs. 5000.  This year it goes down to 4000.  What is the percentage of decrease in price?

Cost of 1000 Articles = 5000, cost of one article = 5000/1000=5

Cost of 1000 Articles = 4000, cost of one article =4000/1000=4

Decrease in price = Rs. 5 – Rs. 4 = Rs. 1

Decrease of % = 1/5 x 100 = 20%

4. Out of 12,000 voters in a constituency, 60% voted.  Find the number of people voted in the constituency.

Percentage of people = 60% of 12,000

No. of people voted = 60/100 x 12000 = 7,200

5. A local cricket team played 20 matches in one season.  If it won 25% of  them and lost rest, how many matches did it loose.

Total No. of matches played = 20

Matches won = 25%, Matches lost = 100 – 25 = 75%

There 75% of 20 = 75/100 x 20 = 15

6. In every gram of gold, a gold smith mixes 0.25gm of silver and 0.05 of copper .  What is the percentage of gold, silver and copper in every gram of gold.

The Quantity of silver = 0.25 gm,

The quantity of copper =0.05 gm.

The quantity of gold = 1gm – (0.25 + 0.05)= 1.00 - 0.30= 0.70gm

Percentage of gold = 7/1 x 100 = 70%

Percentage of silver = .25/1x100 = 25%

Percentage of copper= .05 /1 x 100 = 5%

7.A shopkeeper bought a suitcase for Rs. 480 and sold it for Rs. 540.  Find his gain percent?

Gain = Sp –CP = 540-480= 60,

 Gain % = 60/480 x 100 = 10/8=12.5%

8. Rama bought a T.V. for Rs. 15,000 and sold it for Rs. 20,000.  Find the gain percent ?

Gain= S.P. –CP = 20,000-15,000 = 5,000

Gain % = 5000/15000 x 100 = 100/3= 33.3%

9. Ramu sold a plot of land for Rs. 2,40,000 gaining 20% For how much did he purchase of the plot.

Let C.P.= x, Gain % = 20% of C.P.   S.P. of land =120% of c.P

120% of  x /100 = 24000 = There fore x =100 x 24000/120 =

Ans. Rs. 2,00,000

   

10. On selling a mobile for Rs. 750, a shopkeeper loses 10% For what amount should be sell it to gain 5%?

Let tha c.p of mobile = x  S.P. = 750, loss %= 10  loss= 10x/100

S.P.= C.P.- Loss = x – 10 x/100 =90x/100

There fore 90x /100 = 750, x = 750 x 100/90 = 2500/3

Now tha gain 5% of S.P.= c.P. + 5% of C.P

2500/3 + 5/100x2500/3 =2625/3 = Rs. 875

11. a former sold 2 bullocks for Rs. 24,000 each.  On one bullock he gained 25% on the other he lost 30% Find his total profit or loss percent. 

S.P.= C.P. + Gain = x + 25x/100 = 125x/100 = 24,000

X = 24,000 x 100/125= 19,200

S.P.= C.P.- Loss = y – 20x/100 = 80y/100 = 24,000

Y= 24000  x 100/80 = 30,000

Total C.P. of 2 bullocks = 19000+ 300000= 49,200

Toal S.P. of to bullocks = 24000x 2 = 48000

Loss = c.P.-s.P = 1200

Loss % = 1200/49200 x 100 =2.4%

   

12.Rama bought a watch for Rs. 480.  He sold it to Krishna at a gain of 6 ¼% Krishna sold it to divya at a gain of 10% How much did Divya pay for it?

Cast price of Watch = 480

Gain% = 6 ¼% =25/4%   Gain % = 480 x25/4 x 1/100 = 30

C.P= 480 + 30 =510

Gain = 510 x 10 /100 = 51

S.P. = 510 + 51 = Rs. 561

13.The marked price of a book is Rs. 225.  The publisher allows a discount of 10% on it.  Find the selling price of it.                                                                  

M.P. of the book = Rs. 225-00

Discount = 10%  discount = 225 x 10/100 = Rs. 22.5

S.P. = M.P.- discount = 225.00 - 22.50 = Rs. 202.50

14. A carpenter allows 15% discount on his goods.  Find the marked price of a chair which is sold by him for Rs. 850

Let the M.P. of chair. = x

Discount = 15% = 15x/100

S.P. = M.P. – Discount = x – 15x/100 = 85x /100

S.P. = Rs. 850-00    There ore = 85x/100 x 850-00 =

X = 850 x 100/85 = 1000

M.P. of the chair = Rs. 1000

15. A dealer allows a discount of 10% and still gains by 10%. What should be the marked price if the cost price is Rs. 1000

Given that C.P= Rs. 1000

There is a gain of 10% on C.P.

Gain = 10% of Rs. 1000 = 10 x 1000/ 100 = 100

S.P. = C.P. + Gain = 1000 + 100 = 1100………………(1)

Let M.P. = x

Discount on it = 10% on M.P. = 10 x/100

S.P.=M.P.-Discount = x - 10x/100 =90x/100

From (1) & (2) = 90x/100 =1100    x= 1100 x 100/90 = 11000/9