Question

Find the sum of the following Aps
2, 7,12 ..
to 10 terms​

Answer 1

✴️✌️HEY✌️✴️

a1=2 , a2=7 and a3= 12

now, a2-a1=d

=> d = a2-a1

=>d = 7-2

=>d = 5

then, a10= a+(n-1)d

a10= 2+(10-1)5

a10= 2+45

a10 = 47

:• The 10th term of AP is 47

similarly, a4= 17 , a5 =22 ,a6=27, a7=32 , a8=37

a9=42

Now, the sum of the tenth term of AP is 2+7+12+17+22+27+32+37+42+47 = 245

✴️✌️Thanks ✌️✴️

Answer 2

Answer:

Here a=2 and d= 7-2=5

Xn=a+(n-1)d

=2+(n-1)5

= 5n-3

X 10=(5×10)-3

=47

Sum of n terms of an AP = n/2[Xn+X1]

Sum of 10 terms=10/2[X10+X1]

i.e 5[47+2]

=5×49

=245