Donald swims 3 lengths of a swimming pool in 93 seconds - OCR - GCSE Maths - Question 1 - 2017 - Paper 1

To demonstrate that Donald can swim 100 lengths in under 55 minutes, we first calculate the time it takes for him to swim one length of the pool.

1. Finding the time for one length:
   Donald swims 3 lengths in 93 seconds. Therefore, the time for one length is given by:

   $ext{Time per length} = \frac{93 ext{ seconds}}{3} = 31 ext{ seconds}$

2. Finding the time for 100 lengths:
   To find the total time for swimming 100 lengths, we multiply the time per length by 100:

   $ext{Total time for 100 lengths} = 100 imes 31 ext{ seconds} = 3100 ext{ seconds}$

3. Convert seconds to minutes:
   Next, we convert 3100 seconds into minutes:

   $3100 ext{ seconds} = \frac{3100}{60} ext{ minutes} \approx 51.67 ext{ minutes}$

Since 51.67 minutes is less than 55 minutes, we conclude that Donald could indeed swim 100 lengths in under 55 minutes.