Question

If first term of an AP is 5 and the 10th term is 45, then sum of first ten
terms of the AP is

Answer 1

Answer:

EXPLANATION.

GIVEN

First term of an Ap = 5

10th term of an Ap = 45

To find Sum of ten terms of an Ap

according to the question,

Formula of nth term of an Ap

\bigstar\blue{\boxed{\bold{a_{n} \: = a + ( n \: - 1)d}}}★

a

n

=a+(n−1)d

First term = a = 5

T10 = 45

a + 9d = 45

put the value of a in T10 term

5 + 9d = 45

9d = 40

d = 40/9

To find sum of ten terms

Formula of sum of nth terms

\bigstar\orange{\boxed{\bold{s_{n} \: = \frac{n}{2}(2a \: + (n - 1)d)} }}★

s

n

=

2

n

(2a+(n−1)d)

\bold{s_{10} \: = \frac{10}{2} (2(5) + 9 \times \frac{40}{9} )}s

10

=

2

10

(2(5)+9×

9

40

)

5 ( 10+ 40 )

5 ( 50) = 250

Therefore,

sum of 10th term of an Ap = 250

Step-by-step explanation:

this is use full for you

Answer 2

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