Question

If the 2nd term of an A.P is
an A.P is 4 and 10th term
is 20. Find the 15th term
​

Answer 1

Answer:

According to question,

t2=4

or a+(2-1)*d=4

or,a+d=4..........(1)

and t10 =20

or a+(10-1)d=20

or a+9d=20.........(2)

Solving 1 and 2 by subtracting 1 from 2

8d=16

so d=2

put d=2 in 1

Now a+2=4

so a=2

Now t15=2+(15-1)*2=2+28=30 Is the answer.

Step-by-step explanation:

Answer 2

Step-by-step explanation:

a2 =4

4=2a+d___1

a10= 20

20=2a+9d____2

subtracting equation 1 from equation 2

2a+9d-(2a+d)=20-4

8d=16

d=16/8

=2

from equation 1

2a+2=4

2a=2

a=1

15th term = 2a+(n-1)d

2×1+(15-1)2

2+28

30