Problem 2 · 2019 Math Kangaroo
Easy
Ratios, Rates & Proportions
distance-speed-timeunit-rate
A model railway goes round in circles at a constant speed and needs exactly 1 minute and 11 seconds for one circuit. How long does it need for six circuits?
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Answer: B — 7 minutes 6 seconds
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Hint 1 of 2
One circuit takes 71 seconds; what do six take?
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Hint 2 of 2
Multiply 71 s by 6, then convert back to minutes and seconds.
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Approach: convert to seconds, multiply, convert back
- 1 min 11 s = 71 seconds.
- Six circuits: 6 × 71 = 426 seconds.
- 426 s = 7 min 6 s, so 7 minutes 6 seconds.
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