Question

complete the following activity to find the 19th term of the A. P. 10,15,20.. .
Here, a=10d=......, t19 =?
tn =a+........
t19=10+.........
t19=

activity :Here.a=10, d=5, t19=? ​

Answer 1

Step-by-step explanation:

a=10, a2=15, d=a2-a1 =15-10=5

a19=a+ (n-1) d

10+ (19-1)5

10+ (18)5

10+90

=>100

thereforw, the value of 19th term is 100

Answer 2

Given,

A.P. = 10,15,20,---

To find,

The value of d, and t19.

Solution,

The value of d and t19 for the A.P. 10,15,20,--- will be 5 and 100 respectively.

We can easily solve this problem by following the given steps.

According to the question,

A.P. = 10,15,20,---

The first term (a) = 10

(Note that the common difference is denoted by d.)

Common difference = second term - first term

d = 15-10

d = 5

We know that the formula to find the nth term is given as follows:

tn = a+(n-1)d where n is the number of the term

Now, we have to find the 19th term. So, n = 19.

t19 = 10+(19-1)5

t19 = 10+(18)5

t19 = 10+90

t19 = 100

Hence, the value of d and t19 for the A.P. 10,15,20,--- is 5 and 100 respectively.