In a certain test,$a_i$ students gave wrong answers to at least $i$ questions,where $i = 1, 2, 3, \dots, k$. No student gave more than $k$ wrong answers. The total number of wrong answers given is:

The number of $3$-digit numbers that are divisible by either $3$ or $4$ but not divisible by $48$ is:

If ${A_1}, {A_2}, {A_3}, \dots, {A_{30}}$ are $30$ sets each having $5$ elements and ${B_1}, {B_2}, \dots, {B_n}$ are $n$ sets each having $3$ elements. Let $\bigcup_{i=1}^{30} {A_i} = \bigcup_{j=1}^n {B_j} = S$ and each element of $S$ belongs to exactly $10$ of the $A_i$'s and exactly $9$ of the $B_j$'s,then $n$ is equal to:

There are $100$ students in a class. In an examination, $50$ of them failed in Mathematics, $45$ failed in Physics, $40$ failed in Biology and $32$ failed in exactly two of the three subjects. Only one student passed in all the subjects. Then, the number of students failing in all the three subjects is:

In a cinema hall,the charge per person is $₹ 200$. On the first day,only $60 \%$ of the seats were filled. The owner decided to reduce the price by $20 \%$ and there was an increase of $50 \%$ in the number of spectators on the next day. The percentage increase in the revenue on the second day was (in $\%$)

If $20\%$ of the population of a city travels by car,$50\%$ travels by bus,and $10\%$ travels by both car and bus,then the percentage of people who travel by car or bus is ....$\%$