Ncert solutions mathematics class 8 Solutions for Chapter 15 introduction to graphs

Q1) 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.?

(b) When was the patient’s temperature 38.5° C?

(c) The patient’s temperature was the same two times during the period given. What were these two times?

(d) What was the temperature at 1.30 p.m.? How did you arrive at your answer?

(e) During which periods did the patients’ temperature showed an upward trend?

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.?

(b) When was the patient’s temperature 38.5° C?

(c) The patient’s temperature was the same two times during the period given.

What were these two times?

(d) What was the temperature at 1.30 p.m.? How did you arrive at your answer?

(e) During which periods did the patients’ temperature show an upward trend?

Q2) The following line graph shows the yearly sales figures for a manufacturing company.

(a) What were the sales in (i) 2002 (ii) 2006?

(b) What were the sales in (i) 2003 (ii) 2005?

(c) Compute the difference between sales in 2002 and 2006.

(d) In which year was there the greatest difference between the sales as compared to its previous year?

The following line graph shows the yearly sales figures for a manufacturing

company.

(a) What were the sales in (i) 2002 (ii) 2006?

(b) What were the sales in (i) 2003 (ii) 2005?

(c) Compute the difference between the sales in 2002 and 2006.

(d) In which year was there the greatest difference between the sales as compared to its

previous year?

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 in the following graph.

(a) How high was Plant A after (i) 2 weeks (ii) 3 weeks?

(b) How high was Plant B after (i) 2 weeks (ii) 3 weeks?

(c) How much did Plant A grow during the 3rd week?

(d) How much did Plant B grow from the end of the 2nd week to the end of the 3rd week?

(e) During which week did Plant A grow most?

(f) During which week did Plant B grow least?

(g) Were the two plants of the same height during any week shown here? Specify.

Q3) 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 in the following graph.

(a) How high was Plant A after (i) 2 weeks (ii) 3 weeks?

(b) How high was Plant B after (i) 2 weeks (ii) 3 weeks?

(c) How much did Plant A grow during the 3rd week?

(d) How much did Plant B grow from the end of the 2nd week to the end of the 3rd week?

(e) During which week did Plant A grow most?

(f) During which week did Plant B grow least?

(g) Were the two plants of the same height during any week shown here? Specify.

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?

(b) What was the maximum forecast temperature during the week?

(c) What was the minimum actual temperature during the week?

(d) On which day did the actual temperature differ the most from the forecast

temperature?

Q4) 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?

(b) What was the maximum forecast temperature during the week?

(c) What was the minimum actual temperature during the week?

(d) On which day did the actual temperature differ the most from the forecast temperature?

Use the tables below to draw linear graphs

(a) The number of days a hillside city received snow in different years.

(b) Population (in thousands) of men and women in a village in different years.

Q5) Use the tables below to draw linear graphs.

(a) The number of days a hillside city received snow in different years.

(b) Population (in thousands) of men and women in a village in different years.

A courier-person cycle from a town to a neighboring suburban area to deliver a

parcel to a merchant. His distance from the town at different times is shown by

the following graph.

(a) What is the scale taken for the time axis?

(b) How much time did the person take for travel?

(c) How far is the place of the merchant from the town?

(d) Did the person stop on his way? Explain.

(e) During which period did he ride the fastest?

Q6) A courier-person cycles from a town to a neighboring suburban area to deliver a parcel to a merchant. His distance from the town at different times is shown by the following graph.

(a) What is the scale taken for the time axis?

(b) How much time did the person take for travel?

(c) How far is the place of the merchant from the town?

(d) Did the person stop on his way? Explain.

(e) During which period did he ride the fastest?

Can there be a time-temperature graph as follows? Justify your answer.

Q7) Can there be a time-temperature graph as follows? Justify your answer.

(i)

(ii)

(iii)

(iv)

Plot the following points on a graph sheet. Verify if they lie on a line

(a) A(4,0), B(4, 2),C(4,6), D(4, 2.5)

(b) P(1, 1), Q(2, 2), R(3,3), S(4, 4)

(c) K(2, 3), L(5, 3), M(5,5), N(2, 5)

Q1) Plot the following points on a graph sheet. Verify if they lie on a line

(a) A(4,0), B(4,2), C(4,6), D(4, 2.5)

(b) P(1,1), Q(2,2), R(3,3), S(4,4)

(c) K(2, 3), L(5, 3), M(5, 5), N(2, 5)

Draw the line passing through (2,3) and (3,2). Find the coordinates of the points at

this line meets the x-axis and y-axis.

Q2) Draw the line passing through (2, 3) and (3, 2). Find the coordinates of the points at which this line meets the x-axis and y-axis.

Q3) Write the coordinates of the vertices of each of these adjoining figures.

Write the coordinates of the vertices of each of these adjoining figures.

State whether True or False. Correct that is false.

(i) A point whose x coordinate is zero and y-coordinate is non-zero will lie on the y-axis.

(ii) A point whose y coordinate is zero and x-coordinate is 5 will lie on the y-axis.

(iii) The coordinates of the origin are (0, 0).

Q4) State whether True or False. Correct that is false.

(i) A point whose x coordinate is zero and y-coordinate is non-zero will lie on the y-axis.

(ii) A point whose y coordinate is zero and x-coordinate is 5 will lie on the y-axis.

(iii) The coordinates of the origin are (0, 0).

Q1) Draw the graphs for the following tables of values, with suitable scales on the axes.

(a) Cost of apples

(b) Distance traveled by car

(i) How much distance did the car cover during the period 7.30 a.m. to 8 a.m?

(ii) What was the time when the car had covered a distance of 100 km since it’s started?

(c) Interest on deposits for a year.

(i) Does the graph pass through the origin?

(ii) Use the graph to find the interest on Rs 2500 for a year.

(iii) To get an interest of Rs 280 per year, how much money should be deposited?

Draw the graphs for the following tables of values, with suitable scales on the axes.

(i) How much distance did the car cover during the period from 7.30 a.m. to 8 a.m.?

(ii) What was the time when the car had covered a distance of 100 km since it’s started?

(c) Interest on deposits for a year.

(i) Does the graph pass through the origin?

(ii) Use the graph to find the interest on Rs 2500 for a year.

(iii) To get an interest of Rs. 280 per year, how much money should be deposited?

Q2) Draw a graph for the following.

(i)

Is it a linear graph?

(ii)

Is it a linear graph?

Draw a graph for the following: