Ex.15.1 Q1 Introduction to Graphs Solutions - NCERT Maths Class 8

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The following graph shows the temperature of a patient in a hospital, recorded every hour.

(a) What was the patient’s temperature at \(1\;\rm{pm}\)?

(b) When was the patient’s temperature \(38.5^\circ\rm{C}\)?

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

(d) What was the temperature at \(1.30\;\rm{pm}\)? How did you arrive at your answer?

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

Text Solution


Horizontal axis represents Time and vertical represents Temperature in \(^\circ\,\rm{C.}\)

We can find the value of ‘Temperature’ on vertical axis according to the given value of ‘Time’ on the horizontal axis value or vice versa.


(a) At \(1\;\rm{ pm}\) the patient’s temperature was \(36.5^\circ\,\rm{ C.}\)

(b) The patient’s temperature was \(38.5^\circ\,\rm{ C}\) at \(12\) noon.

(c) The patient’s temperature was \(36.5^\circ\rm{C}\)  at \(1 \,\rm{pm}\) and \(2 \,\rm{pm.}\)

(d) The graph between the times \(1 \,\rm{pm}\) and \(2 \,\rm{pm}\) is parallel to the x-axis. The temperature at \(1 \,\rm{pm}\) and \(2 \,\rm{pm}\) is \(36.5^\circ \;\rm{C.}\) So, the temperature at \(1.30 \;\rm{pm}\) is \(36.5^\circ \;\rm{C.}\)

(e) During \(9 \)am to \(10 \;\rm{pm}\), \(10 \;\rm{pm}\) to \(11 \;\rm{pm}\), \(2\;\rm{pm}\)  to \(3\;\rm{pm}\) , the patient’s temperature showed an upward trend. 

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