Question

If a triangular number pattern is formed using balls, find the number of balls in 7${}^{th}$ term of the pattern.

• A. 25
• B. 26
• C. 27
• D. 28

Answer 1

The correct option is D 28

Given: Triangular pattern of balls

We know that number of items in $n^{th}$ term of a triangular number pattern = $\frac{n(n+1)}{2}$.

So, number of balls in 7${}^{th}$ term = $\frac{7(7+1)}{2}$

Number of balls in 7${}^{th}$ term = $\frac{7\left(8\right)}{2}$

Number of balls in 7${}^{th}$ term = $\frac{56}{2}$

Number of balls in 7${}^{th}$ term = 28