Question

A snail climbs $5$ feet during the day and slips down $4$ feet at night. How many days will it take to first reach the top of a $10$ foot pole?

• A. $5$ days
• B. $6$ days
• C. $7$ days
• D. $8$ days

Answer 1

The correct option is B $6$ days

$\underset{–}{ConceptInvolved:}$

Snail would start from $0$. In a day he climbs $5$ feet. So we add $5$ feet to the reference point i.e. '$0$'. At night, snail slips down $4$ feet so we subtract $4$ feet from $5$ feet that he covered during day.

$\underset{–}{Method:}$

On $1^{st}$ day, snail would cover $5$ feet distance on day and snail would slip $4$ feet distance on night. Total distance covered by the snail on day $1$ would be $1$ feet.

On $2^{nd}$ day, snail would cover $6$(i.e. $5+1$) feet distance on day and snail would slip $4$ feet distance on night. Total distance covered by snail on $2^{nd}$ day would be $2$(i.e. $6-4$) feet.

On $3^{rd}$ day, snail would cover $7$(i.e. $2+5$) feet distance on day and snail would slip $4$ feet distance on night. Total distance covered by snail on $3^{rd}$ day would be $3$(i.e. $7-4$) feet.

On $4^{th}$ day, snail would cover $8$(i.e. $3+5$) feet distance on day and snail would slip $4$ feet distance on night. Total distance covered by snail on $4^{th}$ day would be $4$(i.e. $8-4$) feet.

On $5^{th}$ day, snail would cover $9$(i.e. $4+5$) feet distance on day and snail would slip $4$ feet distance on night. Total distance covered by snail on $5^{th}$ day would be $5$(i.e. $9-4$) feet.

On $6^{th}$ day, snail would cover $10$(i.e. $5+5$) and would reach the top of a $10$ foot pole.

In tabular form, we would observe

Day	$5$	$6$	$7$	$8$	$9$	$10$
Night	$1$	$2$	$3$	$4$	$5$	$10$