The sum of $n$ arithmetic means between $a$ and $b$, is
$\frac{{n(a + b)}}{2}$
$n(a + b)$
$\frac{{(n + 1)(a + b)}}{2}$
$(n + 1)(a + b)$
If ${A_1},\,{A_2}$ be two arithmetic means between $\frac{1}{3}$ and $\frac{1}{{24}}$ , then their values are
$150$ workers were engaged to finish a piece of work in a certain number of days. $4$ workers dropped the second day, $4$ more workers dropped the third day and so on. It takes eight more days to finish the work now. The number of days in which the work was completed is
The sum of $1 + 3 + 5 + 7 + .........$ upto $n$ terms is
A farmer buys a used tractor for $Rs$ $12000 .$ He pays $Rs$ $6000$ cash and agrees to pay the balance in annual instalments of $Rs$ $500$ plus $12 \%$ interest on the unpaid amount. How much will the tractor cost him?