GATE 2024 EE GA Q.8: solution and answer

GATE 2024 · EEGA Q.8 · 2 marks · MCQ

The chart below shows the data of the number of cars bought by Millennials and Gen X people in a country from the year 2010 to 2020 as well as the yearly fuel consumption of the country (in Million liters).

[Chart]

Considering the data presented in the chart, which one of the following options is true?

(A)
The percentage increase in fuel consumption from 2010 to 2015 is more than the percentage increase in fuel consumption from 2015 to 2020.
(B)
The increase in the number of Millennial car buyers from 2015 to 2020 is less than the decrease in the number of Gen X car buyers from 2010 to 2015.
(C)
The increase in the number of Millennial car buyers from 2010 to 2015 is more than the decrease in the number of Gen X car buyers from 2010 to 2015.
(D)
The decrease in the number of Gen X car buyers from 2015 to 2020 is more than the increase in the number of Millennial car buyers from 2010 to 2015.

Answer and solution

ANSWER

(C) The Millennial increase from 2010 to 2015 is 25000 and the Gen X decrease over the same years is only 10000, so (C) is the only true statement.

Official answer: CSource: Official answer key, GATE 2024 EE (IISc Bengaluru)

Read each series against its own axis. The bars use the right axis (number of people buying cars) and the line uses the left axis (Million liters). Gen X: $40000, 30000, 25000$ . Millennials: $20000, 45000, 60000$ . Fuel: $50, 60, 90$ for 2010, 2015 and 2020. (The Gen X 2020 bar and the Millennial 2015 bar end halfway between gridlines, at $25000$ and $45000$ .)
(A) Percentage increase is the increase divided by the starting value. From 2010 to 2015: $\frac{60 - 50}{50} \times 100 = 20%$ . From 2015 to 2020: $\frac{90 - 60}{60} \times 100 = 50%$ . Since $20% < 50%$ , (A) is false.
(B) The Millennial increase from 2015 to 2020 is $60000 - 45000 = 15000$ . The Gen X decrease from 2010 to 2015 is $40000 - 30000 = 10000$ . The claim $15000 < 10000$ is false, so (B) is false.
(C) The Millennial increase from 2010 to 2015 is $45000 - 20000 = 25000$ . The Gen X decrease over the same years is $10000$ . Since $25000 > 10000$ , (C) is true.
(D) The Gen X decrease from 2015 to 2020 is $30000 - 25000 = 5000$ . The Millennial increase from 2010 to 2015 is $25000$ . The claim $5000 > 25000$ is false, so (D) is false.
Only (C) holds. The margin in (C) is large ( $25000$ against $10000$ ), so the result still holds if a halfway bar is misread by a few thousand.

KEY IDEA

This is a dual-axis chart. Read the bars on the right axis (people buying cars) and the fuel line on the left axis (Million liters). Then check each option on exactly the years and the group it names. A percentage change is always the change divided by the value at the start of the period.

WATCH OUT FOR

The usual slip is mixing up the periods. Options (B) and (D) deliberately set one group's change over 2010 to 2015 against the other group's change over 2015 to 2020, and students often compute both over the same period. The second slip is dividing by the end value in (A). That gives 16.7% against 33.3%, which happens to point the same way here but is wrong in method. The third is reading the fuel line on the buyers axis.

From the GATE 2024 EE paper. Every question of this paper · Download the full paper · All 9 Data interpretation questions, with notes

GATE 2024 EE GA Q.8: solution and answer

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