Question

Find the 20th term from the last term of the AP: 3, 8, 13, ...., 253. 164 158 152 182

Solution

The correct option is B 158 We want to find 20th term from the last term of given AP. So, let’s write given AP in this way:  253... 13, 8, 3 First term = a=253 Common Difference = d=8−13=−5 Using formula an=a+(n−1)d,   to find nth term of arithmetic progression, we can say that a20=253+(20−1)(−5) ⇒ a20=253+19(−5)=253−95=158 Therefore, the 20th term from the last term of given AP is 158.

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