CAT 2015 | Question: 93

Question

A young girl counted in the following way on the fingers of her left hand. She started calling the thumb $1$, the index finger $2$, middle finger $3$, ring finger $4$, little finger $5$, then reversed direction, calling the ring finger $6$, middle finger $7$, index finger $8$, thumb $9$, then back to the index finger $10$, middle finger for $11$, and so on. She counted up to $1994$. She ended on her.

• A. thumb
• B. index finger
• C. middle finger
• D. ring finger

Answer 1

Given that, a young girl started calling:

• Thumb – $1,9$
• Index Finger – $2,10$
• Middle Finger – $3,11$
• Ring Finger – $4,12$
• Little Finger – $5,13$
• Ring Finger – $6,14$
• Middle Finger – $7,15$
• Index Finger – $8,16$

From the above information, we can get the pattern: $1,9,17,25, \dots$

We can write, $8n+1, n=0,1,2, \dots$

She counted upto $1994$

That means, $1994 \% 8 = 2$

$\therefore$ If she counted upto $1994,$ she ended on her index finger.

Correct Answer $: \text{B}$