Machine-translated by Google. Questions are authored in English.
Top

Discussion

A frog jumps 3 steps and a rabbit jumps 7 steps at a time starting from a place O. At which of the following steps, they both will be jumping together ?

  • A.343
  • B.371
  • C.378
  • D.354

Answer: C

They will jump together at step 378.

The frog lands on multiples of 3 and the rabbit on multiples of 7, so they meet only on common multiples of 3 and 7, that is, multiples of their LCM, 21.

\[ 378 = 21 \times 18 \]

The others fail one test: 343 = 7 × 49 and 371 = 7 × 53 are multiples of 7 but not of 3 (digit sums 10 and 11), while 354 is a multiple of 3 but not of 7.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.