Question

Look at the pattern and fill in the blanks:

$4=3\times 1+1$, For $1^{\mathrm{st}}$ term or $n=1$

$7=3\times 2+1$, For $2^{\text{nd}}$ term or $n=2$

$10=3\times 3+1$, For $3^{\mathrm{rd}}$ term or $n=3$

$13=3\times 4+1$, For $4^{\mathrm{th}}$ term or $n=4$

$16=3\times 5+1$, For $5^{\mathrm{th}}$ term or $n=5$

$\therefore$Expression for $n^{\mathrm{th}}$ term is $3n+1$

(iii) For $n=30$, $3\times \_\_\_\_+1=\_\_\_\_$.

• A. $30$
• B. $91$

Answer 1

The expression for $n^{\mathrm{th}}$ term is $3n+1$.

Here, $n=30$

Substituting $n=30$ in $3n+1$.

We get, $3n+1$$=3\left(30\right)+1$

$=90+1$

$=91$

Therefore, For $n=30$, $3\times 30+1=91$.