# 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:**

(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)

## 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 apples | 1 | 2 | 3 | 4 | 5 |
---|---|---|---|---|---|

Cost (in Rs.) | 5 | 10 | 15 | 20 | 25 |

(b) Distance travelled by a car

Time (in hours) | 6 AM | 7 AM | 8 AM | 9 AM |
---|---|---|---|---|

Distance (in Km) | 40 | 80 | 120 | 160 |

(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.) | 1000 | 2000 | 3000 | 4000 | 5000 |
---|---|---|---|---|---|

Simple Interest (in Rs.) | 80 | 160 | 240 | 320 | 400 |

(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) | 2 | 3 | 3.5 | 5 | 6 |
---|---|---|---|---|---|

Perimeter (in cm) | 8 | 12 | 14 | 20 | 24 |

Side of square (in cm) | 2 | 3 | 4 | 5 | 6 |
---|---|---|---|---|---|

Area (in cm^{2} | 4 | 9 | 16 | 25 | 36 |