Introduction to Graphs

Exercise 15.2

Question 1: 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)

Answer:

graphs 1

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

graphs 2

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

graphs 3

Exercise 15.3

Question 1: Draw the graphs for the following tables of values, with suitable scales on the axes.

(a) Cost of apples

No. of apples12345
Cost (in Rs.)510152025
graphs 5

(b) Distance travelled by a car

Time (in hours)6 AM7 AM8 AM9 AM
Distance (in Km)4080120160
graphs 7

(i) How much distance did the car cover during the period 7.30 a.m. to 8 a.m?
Answer: 20 km

(ii) What was the time when the car had covered a distance of 100 km since it’s start?
Answer: 7:30 AM


(c) Interest on deposits for a year.

Deposit (in Rs.)10002000300040005000
Simple Interest (in Rs.)80160240320400
graphs 9

(i) Does the graph pass through the origin?
Answer: Yes

(ii) Use the graph to find the interest on Rs 2500 for a year.
Answer: The mid point between 2000 and 3000 is near Rs. 200, so the interest for Rs. 2500 is Rs. 200

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

Answer: Since, to get Rs. 80 per year one needs to deposit Rs. 1000
Hence, to get Re. 1 per year one needs to deposit Rs. 1000/80
Hence, to get Rs. 280 per year one needs to deposit (1000/80) x 280 = Rs. 3500

Question 2: Draw a graph for the following.

Side of square (in cm)233.556
Perimeter (in cm)812142024
graphs 12
Side of square (in cm)23456
Area (in cm249162536
graphs 14


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