Std 7 Mathematics · Chapter 7

7. Joint Bar Graph

Solutions to Practice Set 31 with a drawn joint bar graph for every question. Maharashtra State Board (Balbharati), Grade Seven Mathematics.

Practice Set 31

Steps for every graph: draw the X-axis and Y-axis on graph paper; mark the groups on the X-axis keeping equal gaps between sets of bars; choose a suitable scale for the Y-axis; work out each bar height using the scale; draw the two bars of each set side by side with equal widths and different colours, and add a key (legend).

1The number of saplings planted by schools on World Tree Day is given in the table below. Draw a joint bar graph to show these figures.

Scale: on Y-axis, 1 cm = 10 saplings. The largest value is 72, so the Y-axis goes up to 90.

Bar heights (Nutan Vidyalaya, Bharat Vidyalaya) — Almond: 4 cm and 4.2 cm; Karanj: 6 cm and 3.8 cm; Neem: 7.2 cm and 6 cm; Ashok: 1.5 cm and 2.5 cm; Gulmohar: 4.2 cm and 4 cm.

Joint bar graph — dark bars: Nutan Vidyalaya, light bars: Bharat Vidyalaya

Observation: Nutan Vidyalaya planted the most Neem saplings (72). Bharat Vidyalaya planted more Almond and Ashok saplings than Nutan Vidyalaya.

2The table below shows the number of people who had the different juices at a juice bar on a Saturday and a Sunday. Draw a joint bar graph for this data.

Scale: on Y-axis, 1 cm = 10 people. The largest value is 78, so the Y-axis goes up to 90.

Bar heights (Saturday, Sunday) — Sweet Lime: 4.3 cm and 5.9 cm; Orange: 3 cm and 6.5 cm; Apple: 5.6 cm and 7.8 cm; Pineapple: 4 cm and 6.7 cm.

Joint bar graph — dark bars: Saturday, light bars: Sunday

Observation: More people had every juice on Sunday. Apple juice was the most popular on both days.

3The following numbers of votes were cast at 5 polling booths during the Gram Panchayat elections. Draw a joint bar graph for this data.

Scale: on Y-axis, 1 cm = 100 votes. The largest value is 850, so the Y-axis goes up to 1000.

Bar heights (Men, Women) — Booth 1: 2 cm and 7 cm; Booth 2: 2.7 cm and 2.4 cm; Booth 3: 5.6 cm and 3.4 cm; Booth 4: 8.2 cm and 6.4 cm; Booth 5: 8.5 cm and 4.7 cm.

Joint bar graph — dark bars: Men, light bars: Women

Observation: Women cast more votes than men only at Booth 1. Booth 5 had the most votes by men (850).

4The maximum and minimum temperatures of five Indian cities are given in °C. Draw a joint bar graph for this data.

Scale: on Y-axis, 1 cm = 5 °C. The largest value is 41, so the Y-axis goes up to 50.

Bar heights (Maximum, Minimum) — Delhi: 7 cm and 5.2 cm; Mumbai: 6.4 cm and 5 cm; Kolkata: 7.4 cm and 5.2 cm; Nagpur: 8.2 cm and 5.8 cm; Kapurthala: 7.4 cm and 5.2 cm.

Joint bar graph — dark bars: Maximum, light bars: Minimum

Observation: Nagpur has the highest maximum (41 °C) and the highest minimum (29 °C). The gap between maximum and minimum is greatest in Nagpur (12 °C).

5The numbers of children vaccinated in one day at the government hospitals in Solapur and Pune are given in the table. Draw a joint bar graph for this data.

Scale: on Y-axis, 1 cm = 10 children. The largest value is 89, so the Y-axis goes up to 100.

Bar heights (Solapur, Pune) — D.P.T. (Booster): 6.5 cm and 8.9 cm; Polio (Booster): 6 cm and 8.7 cm; Measles: 6.5 cm and 8.8 cm; Hepatitis: 6.3 cm and 8.6 cm.

Joint bar graph — dark bars: Solapur, light bars: Pune

Observation: For every vaccine, more children were vaccinated in Pune than in Solapur.

6The percentage of literate people in the states of Maharashtra and Gujarat are given below. Draw a joint bar graph for this data.

Scale: on Y-axis, 1 cm = 10 %. The largest value is 83, so the Y-axis goes up to 100.

Bar heights (Maharashtra, Gujarat) — 1971: 4.6 cm and 4 cm; 1981: 5.7 cm and 4.5 cm; 1991: 6.5 cm and 6.1 cm; 2001: 7.7 cm and 6.9 cm; 2011: 8.3 cm and 7.9 cm.

Joint bar graph — dark bars: Maharashtra, light bars: Gujarat

Observation: Literacy rose in both states every decade, and Maharashtra was ahead of Gujarat in every census year.

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