The solution set contained in $R$ of the inequation $3^x+3^{1-x}-4 < 0$ is:

Find all pairs of consecutive odd positive integers,both of which are smaller than $10$,such that their sum is more than $11$.

$A$ triangle is formed by the $X$-axis,$Y$-axis,and the line $3x + 4y = 60$. The number of points $P(a, b)$ which lie strictly inside the triangle,where $a$ is an integer and $b$ is a multiple of $a$,is $...........$

The $I.Q.$ of a person is given by the formula $I.Q. = \frac{MA}{CA} \times 100$,where $MA$ is mental age and $CA$ is chronological age. If $75 < I.Q. < 125$ for a group of $16$ year old children,find the range of their mental age.

The marks scored by Mohan in two tests were $62$ and $48$. Find the minimum marks he should score in the third test to have an average of at least $60$ marks.

$A$ solution of $9 \%$ acid is to be diluted by adding $3 \%$ acid solution to it. The resulting mixture is to be more than $5 \%$ but less than $7 \%$ acid. If there is $460 \text{ L}$ of the $9 \%$ solution,how many litres of $3 \%$ solution will have to be added?