$60 = ? \% \text{ of } 400$

In Convent Model School,$60 \%$ of the students are boys. In an aptitude test,$80 \%$ of the girls scored more than $40$ marks (out of a maximum possible $150$ marks). If $60 \%$ of the total students scored more than $40$ marks in the same test,find the fraction of the boys who scored $40$ marks or less?

The population of a town is $32000$. It increases $15\%$ annually. What will it be in $2$ years?

After giving a $25 \%$ discount on the entry ticket,the number of visitors increased by $30 \%$. What will be the impact on the total revenue from entry tickets compared to other days?

Six-elevenths of a number is equal to $22 \%$ of a second number. The second number is equal to one-fourth of a third number. The value of the third number is $2400$. What is $45 \%$ of the first number?

The value of a machine is $Rs$ $6250$. It decreases by $10 \%$ during the first year,$20 \%$ during the second year,and $30 \%$ during the third year. What will be the value of the machine after $3$ years?