NCERT Class 8 Maths Chapter 13 Introduction to Graphs Exercise 13.1, 13.2 Solutions
In this page we have provided solutions of the Exercises 13.1, 13.2 of NCERT Class 8 Maths Chapter 13 Introduction to Graphs. These solutions are made by our team of expert teachers. Practice these solutions carefully for a better understanding of the topic which will help in scoring good marks in the examination.
Publishing Organisation |
NCERT |
Class |
8 |
Subject |
Mathematics |
Chapter |
13: Introduction to Graphs |
Exercise |
13.1, 13.2 |
Exercise – 13.1
(1) The following graph shows the temperature of a patient in a hospital, recorded every hour.
(a) What was the patient’s temperature at 1 p.m.?
Ans:- At 1 p.m, the patient’s temperature was 36.5°c.
(b) When was the patient’s temperature 38.5° C?
Ans:- The Patient’s temperature was 38.5°c at 12 noon.
(c) The patient’s temperature was the same two times during the period given. What were these two times?
Ans:- The patient’s temperature was same at 1 p.m. and 2 p.m.
(d) What was the temperature at 1.30 p.m.? How did you arrive at your answer?
Ans:- The graph between the times 1 p.m. and 2 p.m. is parallel to the x – axis. The temperature at 1.
(e) During which periods did the patients’ temperature showed an upward trend?
Ans:- During the following periods, the patient’s temperature showed an upward trend. 9 a.m. to 10 a.m., 10 a.m. to 11 a.m. 2 p.m. to 3 p.m.
(2) The following line graph shows the yearly sales figures for a manufacturing company.
(a) What were the sales in:
(i) 2002
(ii) 2006?
Ans:- The Sales in
(i) 2002 were Rs 4 corers and in (ii) 2006 were Rs 8 crores.
(b) What were the sales in
(i) 2003
(ii) 2005?
Ans:- The Sales in
(i) 2003 were Rs 7 corers and in (ii) 2005 were Rs 10 crores
(c) Compute the difference between the sales in 2002 and 2006.
Ans:- The difference between the sales in 2002 and 2006 = Rs 8 corers – Rs 4 corers = Rs 4 corers.
(d) In which year was there the greatest difference between the sales as compared to its previous year?
Ans:- The difference between sales in 2002 and 2003
= Rs 7 corers – Rs 4 corers = Rs 3 corers
The difference between sales in 2003 and 2004
= Rs 7 corers – Rs 6 corers = Rs 1 corers
The difference between sales in 2004 and 2005
= Rs 10 corers – Rs 6 corers = Rs 4 corers
The difference between sales in 2005 and 2006
= Rs 10 corers – Rs 8 corers = Rs 2 corers
Therefore, in year 2005 the difference between the sales as compared to its previous year was the greatest.
(3) For an experiment in Botany, two different plants, plant A and plant B were grown under similar laboratory conditions. Their heights were measured at the end of each week for 3 weeks. The results are shown by the following graph.
(a) How high was Plant A after (i) 2 weeks (ii) 3 weeks?
Ans:- (i) After 2 weeks the height of plant A was 7 cm.
(ii) After 3 weeks. The height of plant A was 9 cm.
(b) How high was Plant B after (i) 2 weeks (ii) 3 weeks?
Ans:- (i) After 2 weeks the height of plant B was 7 cm.
(ii) After 3 weeks. The height of plant B was 10 cm.
(c) How much did Plant A grow during the 3rd week?
Ans:- Growth of plant Ad wring 3rd week = 9 cm – 7cm = 2cm
(d) How much did Plant B grow from the end of the 2nd week to the end of the 3rd week?
Ans:- Growth of Plant B form the end of the 2^{nd} week to the end of the 3^{rd} week = 10 cm – 7 cm = 3 cm
(e) During which week did Plant A grow most?
Ans:- Growth of plant ad wring 1^{st} week = 2 cm – 0 cm = 2 cm
Growth of plant A during 2^{nd} week = 7 cm – 2 cm = 5 cm
Growth of plant Ad wring 3^{rd} week = 9cm – 7 cm = 2 cm
Therefore, Plant A grew the most, i.e., 5 cm, during the 2^{nd} week.
(f) During which week did Plant B grow least?
Ans:- Growth of plant B during 1^{st} week = 1 cm – 0 cm = 1 cm
Growth of plant B during 2^{nd} week = 7 cm – 1 cm = 6 cm
Growth of plant B during 3^{rd} week = 10 cm – 7 cm = 3 cm
Therefore, Plant B grew the least, i. e., 1 cm, during the 1^{st} week.
(g) Were the two plants of the same height during any week shown here? Specify.
Ans:- At the end of the 2^{nd} week, the heights of both plants were same.
(4) The following graph shows the temperature forecast and the actual temperature for each day of a week.
(a) On which days was the forecast temperature the same as the actual temperature?
Ans:- The fore cast temperature was same as the actual temperature on Tuesday, Friday, and Sunday.
(b) What was the maximum forecast temperature during the week?
Ans:- The maximum fore cast temperature during the week was 35°c.
(c) What was the minimum actual temperature during the week?
Ans:- The minimum actual temperature during the week was 15°c.
(d) On which day did the actual temperature differs the most from the forecast temperature?
Ans:- The actual temperature differs the most from the forecast temperature on Thursday.
Chapter 12: Factorisation