NCERT Solutions for Class 7th Maths Chapter 5 Figure it Out — Visualising Data

Yes, it is a bar graph — each animal gets one bar whose length stands for its top speed, all measured on the same scale. The pictures, the shading and the little stories are decoration added on top; strip them away and a plain bar graph remains. The three shades group the animals into speed in air, speed on land and speed in water.

(a) The scale. The marks read 0, 16, 32, 48, 64, 80, 96, 112, 129, 145, … up to 322 kph, so 1 unit length ≈ 16 kilometres per hour. The odd-looking numbers are there because the original figures were in miles per hour: each mark is 10 mph, and 10 mph ≈ 16 kph.

(b) What is interesting, and what to explore.

• The fastest animal is a bird, not a big land animal — the peregrine falcon at 322 kph, three times faster than a cheetah.
• The flying fish (56 kph) appears in the air group, not the water group. It glides above the sea.
• The Australian tiger beetle is the slowest at 8 kph — yet it covers about 120 body lengths every second, far more than the cheetah does. Speed measured in body lengths tells a different story from speed in kph.
• Only one water animal beats the fastest land animal: the sailfish (109 kph) edges past the cheetah (103 kph).
• To explore: how fast are these animals in body lengths per second? Can any animal keep up its top speed for a whole minute? Why can nothing in water go as fast as things in air?

(c) A pair where one is about twice the other. Several pairs work:

(d) Two claims — and neither can be checked from this graph.

• "A sailfish is about 4 times faster than a humpback whale." The humpback whale does not appear anywhere in this infographic. The graph gives us 109 kph for the sailfish and nothing at all for the whale, so we cannot test the claim. To check it we would need the whale's top speed from some other source. (It would have to be about 109 ÷ 4 ≈ 27 kph for the claim to hold.)
• "A sailfish is the fastest aquatic animal in the world." The graph shows only four water animals — sailfish, dolphin, California sea lion and Gentoo penguin. All the graph proves is that the sailfish is the fastest of these four. The oceans hold thousands of species that are not on this chart.

First count each letter. Both grades have 25 students, so the two sets of bars can be compared directly.

Choosing a scale. The largest count is 13, so a vertical line up to 14 is enough. Take 1 unit length = 2 students — that gives 7 gridlines at 0, 2, 4, 6, 8, 10, 12, 14, and every count sits on or halfway between gridlines.

Observations.

• Aquatic is the one option both grades chose equally — 6 students each.
• Grade 5 loves flying: 13 of 25 students, more than half the class, chose aerial. Only 2 chose spaceborne.
• Grade 9 leans to space: 9 chose spaceborne against Grade 5's 2 — more than four times as many.
• Twice as many Grade 5 students (4) chose none as Grade 9 students (2).

With the scale 1 unit = 4°C, the vertical line is marked 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44. The highest reading is 43°C, so 44 is the top gridline.

Which months? Day 2 is a peak-summer day — May or June. It never falls below 30°C, not even at dawn, and reaches 43°C in the afternoon. Day 1 is a much cooler day whose afternoon still touches 34°C but whose dawn drops to 16°C — that fits a cooler month such as February–March, or October–November. It is too warm in the afternoon for the depth of winter and far too cool at dawn for high summer.

First, read the five states already drawn. The gridlines are 5000 apart, so each bar can be read to the nearest few thousand.

(a) Marking the Gujarat and Delhi bars. Work out where each top goes, counting gridlines of 5000 from the labelled marks 0, 25000, 50000, 75000 and 100000.

• Gujarat 2022, 69,000 — between 65,000 and 70,000, nearer 70,000.
• Gujarat 2023, 89,000 — between 85,000 and 90,000, nearer 90,000. This is the tallest bar in the whole graph.
• Gujarat 2024, 78,000 — between 75,000 and 80,000, just above the 75,000 line.
• Delhi 2022, 62,000 — between 60,000 and 65,000.
• Delhi 2023, 74,000 — just below the 75,000 line.
• Delhi 2024, 81,000 — between 80,000 and 85,000.

(b) How the graph is organised. Each state has three bars side by side — blue for 2022, red for 2023, yellow for 2024 — and the states run along the bottom. The vertical line is labelled every 25,000 with fainter lines every 5,000, and it reaches 100,000. The states are arranged roughly from smallest to largest, which makes the overall rise easy to see.

(c) Describing the change from 2022 to 2024.

Every state registered more electric vehicles in 2024 than in 2022. The states that started small grew the fastest in proportion; the states that started large added the most vehicles in number.

(d) Assam, 2023 compared with 2022.

(e) West Bengal, 2022 to 2024.

(f) Is the statement correct? No — the reasoning in it is wrong.

• The bars show how many vehicles were registered in each year separately, not a running total. So Uttarakhand's 2023 bar means about 17,000 new registrations in 2023 alone, and its 2024 bar means about 19,000 more in 2024.
• That is about 36,000 new electric vehicles in two years — nobody would call that "very few".
• What the small change in bar length really shows is that Uttarakhand's yearly number is growing slowly, not that few vehicles are being registered.