Two-fifths of one-third of three-seventh of a number is $15$. What is $40$ per cent of that number?

In an examination,it is required to get $35 \%$ of the aggregate marks to pass. Rishu got $216$ marks and was declared failed by $5 \%$ marks. What was the total marks?

Raja got $76 \%$ marks and Seema got $480$ marks in a test. The maximum marks of the test is equal to the marks obtained by Raja and Seema together. How many marks did Raja score in the test?

$A$ boy found the answer for the question "subtract the sum of $\frac{1}{4}$ and $\frac{1}{5}$ from unity and express the answer in decimals" as $0.45$. The percentage of error in his answer was

$x\%$ of $360 = 129.6$. Find $x$.

The monthly income of a person is $Rs. 5000$. If his income is increased by $30\%$,then what is his monthly income now?