Question

find the sum of 2,7,12,...to 10 terms​

Answer 1

2+7+12+17+22+27+32+37+42+47=245

Answer 2

Answer:

245

Step-by-step explanation:

AP : 2, 7, 12,....., to 10 terms.

Here, we have ;

First term (a) = 2

Number of terms (n) = 10

Difference (d) = 7 - 2 = 5

Sum of n terms is given by formula :

$\bf S_n = \frac{n}{2}[2a +(n-1)d] \\ \\ \bf S_{10} = \frac{10}{2}[2 \times 2+(10-1)5] \\ \\ \bf S_{10} = 5 [4 + 9 \times 5] \\ \\ \bf S_{10}= 5[ 4 + 45]\\ \\ \bf S_{10}= 5 \times 49 \\ \\ \red{\boxed{\bf S_{10} = 245}}$

Hence, the sum of the given AP is 245.