NCTB Class 6 Math Chapter Two Exercise 2.3 Solution by Math Expert. Bangladesh Board Class 6 Math Solution Chapter 2 Ratio’s & Percentages Exercise 2.3 Solution.
Ratio’s & Percentages
(1) In the following chart, match the expression of the left to that of the right.
|(a) Ratio||(a) %|
|(b) Unit ratio||(b) a fraction|
|(c) Symbol of percentage||(c) 1:5|
|(d) Ratio in greater inequality||(d) 9:9|
|(e) Ratio in less inequality||(e) 7:3|
(2) What is ratio?
Solution:- Ratio is (a) A fraction.
(3) Which is the equivalent ratio of 2:5 of the followings?
Solution:- The equivalent ratio of 2:5 is— (c) 4:10
(4) Which of the following is the compound ratio of 3:4 and 4:5?
Solution:- The compound ratio of 3:4 and is – (b) 12:20
(5) If the ratio 3:20 is expressed into percentage, which of the following is correct?
3:20 = 3/20 x100
(6) 1% of 200 centimetre is –
Solution:- 15 of 200cm is – (c) 2cm
(7) In the ratio 1:5
Solution:- In the ratio 1:5 – (d) (i), (ii), (iii) Correct Answer.
(8) Of 100 boys and girls, if 60% is girls
Solution:- The correct answer is – (d) (i), (ii), (iii)
(9) What is the ratio of the marked part and the whole part of the diagram?
Solution:- Ratio the marked part and the whole part of the diagram is – (a) 1:4
(10) What is the area of the greatest square of the diagram?
Solution:- Area f greatest square of diagram is – (d) 4 square meter.
(11) How many men’s work can 9 boys do?
Solution:- (b) 6 persons.
(12) What amount of money would each boy get if 3 boys would do the work?
Solution:- (d) 300 Taka [900/3 = 300]
(13) Yousuf have obtained 70% of marks. What marks has yousuf obtained if the total marks of examination are 700?
Solution:- Total marks = 700
Yousuf obtained = 70% of total marks.
Therefore, He obtained = 700x 700/100
(b) = 490 Answer.
(14) What is the price of 5kgs of rice if the price of 8kgs of rice is TK.168?
Solution:- Price of 8kg’s rice = 168
Therefore, price of 1kg’s rice = 168/8
Therefore, price of 5kg’s rice = 168×5/5
(15) What will be the price of 15kgs of rice if the price of 7kgs of rice is TK.280?
Solution:- Price of 7kgs rice = TK.280
Therefore, price of 1kg’d rice = 280/7
Therefore, price of 15kg’s rice = 280×15/7
(16) In hostel there was food stored for 50 students for 15days. For how many days will 25students be served by that quantity of food?
Solution:- Food stored for 50 students for 15days
Therefore, food stored for 25 students for 15/50×25
= 7.5 days.
(17) A shopkeeper by investing TK.9000 makes a profit of TK.450 daily. How much money is to be invested if he wants to make a profit of TK.600 daily?
Solution:- For, 450 profit investing TK.9000
Therefore, 1 profit investing TK.900/450
Therefore, 600 profit investing (9000/450×600)
= 1200 Rs/- to be invested.
(18) 10 persons can be served for 27days with 120kgs of rice. How many kgs. of rice are needed to serve the same number of persons for 45days?
Solution:- 27 days with 120kgs of rice
Therefore, 1 days with 120/27
Therefore, 45 days with 120×45/27
= 200kgs of rice.
(19) There are 2 quintals of rice for 15 students for 30days. How many days will be required to serve 20 students with the same quantity of rice?
Solution:- 2 quintal rice for 15 students for 30 days
2 quintal for 20 students for = 30×15/20
= 22 1/2days.
(20) There are 25 students living in a hostel. They need 625 gallons of water in a week. How many students will be able to fulfil their needs if there are 900 gallons of water?
Solution:- 625 gallons water need for 25 students .
1 gallons water need for 25/625 students
900 gallons water need for = 25×900/625 students
= 36 students.
(21) 9 workers can do a piece of work in 18days. In how many days can 18 workers do that piece of work?
Solution:- 9 workers can do a piece of work 18 days.
Therefore, 1 workers can do a piece of work 18×9
Therefore, 18 workers can do a piece of work 18×9/18
= 9 days Answer.
(22) 360 workers can construct an embankment in 25days. How many extra workers are needed to finish the constructions in 18days.
Solution:- In 25 days embankment construct 360 workers
Therefore, 1days embankment construct 360×25 workers
Therefore, 18 days embankment construct 360×25/18 workers
= 500 workers.
Therefore, Extra worker needed
= 140 workers. Answer.
(23) By working 6 hours daily 25 persons can do a piece of work in 8 days. In how many kilometres does the run in 6days and what is his speed?
Solution:- 25 persons working 6 hours daily, days
Therefore, (6×8) = 48 hours total
25 persons do work 6hr daily 8 hours
10 persons do work 6hr daily 8x25x6/10×6
= 20 days.
(24) A school students crosses 10km. in 2 hours by cycling from his house to school. How many kilometres does he run in 6 days and what is his speed?
Solution:- Student, in 2hr crosses 10km
Therefore, in 6days
His speed = 60/12
= 5km/hr. Answer.
(25) Walking 10hours daily Rabin crosses 480km in 12days. In how many days can he cross 360km walking 9 hours daily?
Solution:- Rabin 12×10 =120hr crosses
Walking 10hr daily in 12 days crosses 480km
Therefore, Walking 1hr daily in 1 days crosses 480km
Speed = 480/10×12
360km distance cross by walking 9hrs daily days required = 360/4×9
= 10days. Answer.
(26) Jalal crosses 9km path in each 3 hours does he need to cross 36km?
Solution:- Jalal speed = 9/3 km/hr
To cross 36 km time taken
= 12days (Answer)
(27) 6 workers can reap crops of a field in 28days. In how many days will 24 workers reap the crops of that field?
6 workers can reap crops of field in 28 days
Therefore, 1 workers can reap crops of a field in 28×6/24
= 7 day (Answer)
(28) 2 men can do the same amount of work that 3 boys can do. 4 men and 10 boys together can do a piece of work in 21 days. In how many days will 6 men and 15 boys do that work?
4 men and 10 boys together can do work in 21 days
Therefore, 1 men and 10 boys together can do work in 21x4x10
Therefore, 6 men and 15 boys together can do works in 21x4x10/6×15 days
=21 days (Answer)