Question

How many toothpicks would be in the tenth figure?
A) 21
B) 20
C) 11
D) 23​

Answer 1

Option (A)

Explanation:

From the picture attached,

Number of toothpicks used in every figure form a sequence as,

3, 5, 7, 9.......

It's an Arithmetic progression having,

First term 'a' = 3

Common difference 'd' = 5 - 3 = 2

Since, nth term of an A.P. is given by the formula,

`T_n=a+(n-1)d`

Therefore, 10 figure will have number of toothpicks as,

`T_(10)=3+(10-1)2`

= 3 + 18

= 21

21 toothpicks will be in the 10th figure of the given sequence.

Option (A) will be the answer.