$A$ student secures $90\%$,$60\%$ and $54\%$ marks in test papers with $100$,$150$ and $200$ respectively as maximum marks. The percentage of his aggregate is:

$A$ student multiplied a number by $\frac{3}{5}$ instead of $\frac{5}{3}$. What is the percentage error in the calculation (in $\%$)?

$23 \% \text{ of } 6783 + 57 \% \text{ of } 8431 = ?$

Rita invested $25 \%$ more than Sunil. Sunil invested $30 \%$ less than Abhinav,who invested $Rs$ $6,000$. What is the ratio of the amount that Rita invested to the total amount invested by all of them together?

When a number is divided by $12$,the quotient is $\frac{1}{4}$ of another number. By what percentage is the first number greater than the second number?

Asha's monthly income is $60 \%$ of Deepak's monthly income and $120 \%$ of Maya's monthly income. What is Maya's monthly income,if Deepak's monthly income is Rs. $78000$?