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

Answer:
Option (A)
Step-by-step 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,
[tex]T_n=a+(n-1)d[/tex]
Therefore, 10 figure will have number of toothpicks as,
[tex]T_{10}=3+(10-1)2[/tex]
= 3 + 18
= 21
21 toothpicks will be in the 10th figure of the given sequence.
Option (A) will be the answer.