which term of the ap 20, 19 4 1 , 18 2 1 , 17 4 3 , ... is the first negative term.

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get which term of the ap 20, 19 4 1 , 18 2 1 , 17 4 3 , ... is the first negative term. from screen.

Which term of the progression 20,19 1/4, 18 1/2, 17 3/4..is the first negative term?

Byju's Answer Standard X Mathematics Nth Term of a GP Which term of... Question

Which term of the progression

20 , 19 1 4 , 18 1 2 , 17 3 4

..is the first negative term?

Open in App Solution Given, A.P. is 20 , 19 1 4 , 18 1 2 , 17 3 4 . . . = 20 , 77 4 , 37 2 , 71 4 , . . . . Here, a = 20, d = 77 4 − 20 = 77 − 80 4 = − 3 4 Let a n

is first negative term

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⇒ a + ( n − 1 ) d 0 ⇒ 20 + ( n − 1 ) ( − 3 4 ) 0 ⇒ 20 + 3 4 3 4 n ⇒ 83 4 3 4 n ⇒ n > 83 4 × 4 3 ⇒ n > 83 3 = 27.66 28 t h

term will be the first negative term of given A.P.

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Which term of A.P. 20, 19 1/4, 181/2 ,..... is first negative term?

Click here👆to get an answer to your question ✍️ Which term of A.P. 20, 19 1/4, 181/2 ,..... is first negative term?

Which term of A.P. 20,19

Question 4 1 ,18 2 1

,..... is first negative term?

!8th

15th

28th

27th

Easy Open in App Solution Verified by Toppr

Correct option is C)

20,19

4 1 ,18 2 1 ,.... or 20, 4 77 , 2 37 ,.... a=20 d= 4 77 −20= 4 −3 Let n th

term of A.P. be first negative term

So, 20+(n−1)( 4 −3 )<0 ⇒80−3n+3<0 ⇒3n>83 ⇒n>27 3 2 Hence, 28 th

term is first negative term.

(Option 3).

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Which Term of the Ap `20, 19 1/4 , 18 1/2 , 17 3/4 ` ,..... is the First Negative Term?

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Which term of the AP

20,1914,1812,1734

,..... is the first negative term?

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SOLUTION

The given AP is 20,1914,1812,1734 ,..... and

Here,a=20andd=1914-20=774-20=77-804=-34

Let the nth term of the given AP be the first negative term. Then,

an < 0

⇒20+(n-1) ×(-34)<0 [an=a+(n-1)d]

⇒20+34-34n<0 ⇒834-34n<0 ⇒-34n<-834 ⇒n>833=2723 ∴ n= 28

Hence, the 28th term is the first negative term of the given AP.

Concept: Sum of First n Terms of an A.P.

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Chapter 11: Arithmetic Progression - Exercises 1

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RS Aggarwal Secondary School Class 10 Maths

Chapter 11 Arithmetic Progression

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