Unit 3 · Measurement and Data
Unit Conversion — Which Calculation Is Correct?
Lesson 1 of 13
To convert days to seconds, you chain three multiplications: days × 24 (hours in a day) × 60 (minutes in an hour) × 60 (seconds in a minute). Each step converts one unit to the next smaller unit.
Unit-conversion chain questions appear in the very-easy band of Selective MR — reliable marks when you write out the chain step by step rather than guessing from the options.
The examiner tests whether students know the three conversion factors (1 day = 24 h, 1 h = 60 min, 1 min = 60 s) and chain them correctly. Common traps: stopping at hours (24×24) or minutes (24×60), or omitting the day→hour factor.
A question asks for the calculation (not the result) that converts a number of days into seconds. Students identify the correct chain of multiplication.
Best approach: Write the chain: days × (hours/day) × (min/hour) × (s/min) = 24 × 24 × 60 × 60. The first 24 is the number of days; the second 24 is hours per day.
Question
Which of the following calculations shows how to work out the number of seconds in 24 days?
Select an answer to see the explanation.
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