Question

which term of A.P: 3,6,9,12,...is 78​

Answer 1

Step-by-step explanation:

26 term is 78

hope this will help you..

Answer 2

Step-by-step explanation:

$3, \: \: 6, \: \: 9, \: \: 12, \: \: ..., \: \: 78 \\ Here, \\ First \: \: term \rightarrow a = 3 \\ Difference \rightarrow d = 6 - 3 = 3 \\ \\ T_{n} = a + (n - 1)d \\ 78 = 3 + (n - 1)3 \\ 78 = 3 + 3n - 3 \\ 78 = 3n \\ \frac{78}{3} = n \\ \bf \underline{ \underline{26}} = n \\ \\ \therefore \: \: {26}^{th} \: \: term \: \: of \: \: the \: \: series \: \: is \: \: 78$