Question

term
of
The
AP
3, 8, 13, 18
787
Findn.​

Answer 1

CORRECT QUESTION:-

The A.P when the following progression is given of 3,8,13,18-------- ,78. Find n.

Step-by-step explanation:

Here a is 3.

Here an is 78.

The difference is 5.

n = ?

Here, we know the formula,

an = a + (n-1)d

78 = 3 + (n-1)5

78 = 3 + 5n - 5

78-3= 5n-5

75 = 5n-5

5n=7/+5=80

n=80/5

n= 16.

Hence, the answer is 16.

WHAT IS A.P?

A.P stands for Arithmetic Progression. It is used to find a particular number in an arranged pattern or find that in which term the number will come.

______________________________________

FORMULA USED

For finding A.P, we use the following formulas

• $a(n) = a + (n - 1) \times d$

Here, d stands for common difference , a stands for First term of progression & a(n) stands for Last term of progression & also, n stands for number of terms.

• $s(n) = \frac{n}{2} \times (a + a(n))$
• Where S(n) stands for sum of numbers and rest stands the same.

________

NOTE: The reason that the last term can't be 787 is n can never be in decimal or in negative.

As per this , n= 157.8 which in case, cannot be.