ICSE & CBSE Board Question Based on Arithmetic Progression of RS Aggarwal

In this Question which term of the AP is the first negative term of the given AP.

This is the Question Number 11 Of Exercise 11D of RS Aggarwal Solution

Deepak BoraNewbie

# Which term of the AP 25,20,15,…is the first negative term ?

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We can conclude that the first term

a = 25

And the common difference(d)

d = 20-25

d = – 5

For finding the A. P.:–We can use the formula

An = a+(n-1)d

As we know:–Forthe first negative term it should be less than 0.

So the required equation will be :=> a+(n-1)d<0

=> 25+(n-1)*(-5)<0

=> (n-1)*(-5)<-25

=>(n-1)>5

=> n>6

Therefore-:The first negative term is it’s 7th term.