The following bar chart shows the year-wise percentage hike in the fuel price with respect to the previous year. Fuel price hike (in %) 2015 — 8 2016 — 10.5 2017 — 6 2018 — 7 2019 — 8 2020 — 10 2021 — 11 In how many years did the fuel prices NOT rise?

Correct — D. The bar chart plots the percentage hike in the fuel price with respect to the previous year — a rate of change, not the price itself.

The seven bars read: 2015 = 8, 2016 = 10.5, 2017 = 6, 2018 = 7, 2019 = 8, 2020 = 10, 2021 = 11.

Every one of those is positive, so the price went up in each of the seven years.

Years in which the price did not rise = 0 → option (d).

Why the others are wrong

• (a)
  1 — 1 counts 2017, where the bar falls from 10.5 to 6. What dropped is the rate of increase — a 6% hike is still a hike.
• (b)
  5 — 5 would need five of the seven bars to be zero or negative. None is: even the shortest bar, 2017, stands at 6%.
• (c)
  2 — 2 counts the two shortest bars, 2017 at 6 and 2018 at 7, as flat years. Both are positive hikes, so the price rose in both.

This is a chart of change, not of level, and the two behave differently.

A price rises in any year whose bar is above zero. It falls only if a bar goes below zero, and it stands still only at exactly zero.

A bar shorter than last year's — 2017 after 2016 here — means the price climbed more slowly, from a base that was already higher. Read against zero, not against the neighbouring bar.

Key facts

• The bars show the percentage hike over the previous year, so the price level rises whenever a bar is above zero.
• A shorter bar than the year before means slower growth, not a price cut.
• The chart runs from 2015 to 2021 and its smallest bar is 2017 at 6%.

Common traps

• Reading the dip at 2017 as a fall in the fuel price.
• Comparing each bar with the neighbouring bar instead of with zero.
• Answering how many years the hike shrank rather than how many had no rise.

No directly related past PYQ was found.