$A$'s salary is $50 \%$ more than $B$'s. How much percent is $B$'s salary less than $A$'s?

$A$ man spends $75 \%$ of his income. His income increases by $20 \%$ and his expenditure also increases by $10 \%$. The percentage of increase in his savings is (in $\%$)

In the last financial year,a car company sold $41,800$ cars. In this year,the target is to sell $51,300$ cars. By what percent must the sale be increased?

Ram gets $20\%$ marks more than Girish. Girish gets $20\%$ more than Sanjay. Sanjay gets $20\%$ less than Aditya. If Ram got $576$ marks and the total marks were $800$,then what marks did Aditya get?

Sashi has $Rs. 90000$ with him. He purchases a mobile,an iPad,and a laptop for $Rs. 15000$,$Rs. 13000$,and $Rs. 35000$ respectively and puts the remaining money in his bank account which pays $15 \%$ per annum compound interest. After $2$ years,he sells off the three items at $80 \%$ of their original price and also withdraws his entire money from the bank by closing the account. What is the total percentage change in his assets (in $\%$)?

In an examination,$37 \frac{1}{2} \%$ of the candidates were girls. If $75 \%$ of the boys and $62 \frac{1}{2} \%$ of the girls passed,and $342$ girls failed,find the number of boys who failed.