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:

Rohith spends $40\%$ of his salary on food, $20\%$ on house rent, $10\%$ on entertainment and $10\%$ on conveyance. If his savings at the end of a month are Rs. $1500$, then his monthly salary is:

From the salary of an officer, $10\%$ is deducted as house rent, he spends $20\%$ of the rest on conveyance, he pays $20\%$ of the rest as income tax, and he spends $10\%$ of the balance on clothes. Then, he is left with Rs. $15,552$. Find his total salary.

Aman gave $40\%$ of the amount he had to Rohan. Rohan, in turn, gave one-fourth of what he received from Aman to Sahil. After paying Rs. $200$ to the taxi driver out of the amount he got from Rohan, Sahil now has Rs. $600$ left with him. How much amount did Aman have?

$405$ sweets were distributed equally among children in such a way that the number of sweets received by each child is $20\%$ of the total number of children. How many sweets did each child receive?

$37\frac{1}{2}\%$ of the candidates in an examination were girls, $75\%$ of the boys and $62\frac{1}{2}\%$ of the girls passed and $342$ girls failed. The number of boys failed was:

Peter could save $10\%$ of his income. But two years later when his income is increased by $20\%$ he could save the same amount as before. By how much percent has his expenditure increases?