TIFR CSE 2022 | Part A | Question: 1

Question

A snail crawls up a vertical pole $75$ feet high, starting from the ground. Each day it crawls up $5$ feet, and each night it slides down $4$ feet. When will it first reach the top of the pole?

• A. $75^{\text {th}}$ day
• B. $74^{\text {th}}$ day
• C. $73^{ \text{rd}}$ day
• D. $72^{\text {nd }}$ day
• E. $71^{\text {st }}$ day

Answer 1

Snail crawls up in day 5 fit

 Snail crawls down in a night 4 Fit

now over all crawls in a day 5-4= 1 fiit

2nd day 1 fit ...... .… =2 fit

...........

70th  day 70 fit

71th day 5 fit up

70 + 5= 75 fit

Snail will first reach top in 71th  day