Which term of the AP : 32, 27, 22, . . . is – 78?

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16 Nov 2020 ARITHMETIC PROGRESSIONS

Which term of the AP : 32, 27, 22, . . . is – 78?

OPtion

1) 35
2) 32
3) 29
4) 27
5) 20
6) 23
7) 21
8) 30
9) 25
10) None of the above

Solution

Here, a = 32, d = 32 – 27 = – 5 and an = – 78,
As:- an = a + ( n – 1) d,
– 78 = 32 + (n – 1)(– 5),
– 78 = 37 – 5n,
– 115 = – 5n,
So, n = 23

Correct Option: 6 Best Solution (1)