Q. 64.2( 241 Votes )

# Check whether – 150 is a term of the AP : 11, 8, 5, 2 . . .

Answer :

**To find: Whether -150 is term of the APGiven: a = 11, d = 8 – 11 = - 3, a**We know that a

_{n}= - 150, n = ?

_{n}= a + (n – 1)d

_{n}= nth term of AP

a = first terms of AP

n = no. of terms of AP

d = common difference of AP

Applying the formula, we get

Or, - 150 = 11 + (n – 1)(- 3)

Or, (n – 1)(-3) = - 150 – 11 = - 161

Or, n – 1 = 161/3

n - 1 = 53.67

It is clear that 161 is not divisible by three and we shall get a fraction as a result. But number of term cannot be a fraction.

**Hence, - 150 is not a term of the given AP.**

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