A bus takes $10$ hours to reach a destination by travelling at a speed of $65 km/h$. What should be its speed to reach the destination in $13$ hours?

If $45$ girls can consume a stock of food in $2$ months, then for how many girls the food stock is sufficient for $100$ days?

If $88$ cows can graze a field in $36$ days, in how many days will $12$ cows graze the same field?

Rahul cycles at a speed of $6 km/h$ to reach school in $20$ minutes. What should his speed be if he wants to reach school in $15$ minutes?

The annual fee of a school for one child is increased from $₹4,800$ to $₹6,000$. Find the percentage increase in the fees.

In a factory $55\%$ of the workers are females. If the number of male workers is $720$, then find the number of female workers and total number of workers in the factory.

Out of a batch of $75$ students, $72\%$ are good at mathematics. Find the number of students who are not good at mathematics.

In a class of $60$ students, $60\%$ like vanilla flavour, $25\%$ like butterscotch, and the remaining like chocolate flavour. Find the number of students who like vanilla, butterscotch and chocolate flavours separately.

Mr. Gupta tells us that $15\%$ of his salary is deducted as monthly income tax. If he receives $₹25,50,000$ per annum after deductions, then find Mr. Gupta's gross salary.