Three friends Ankit, Bholu and Chetan has average weight of 88 Kg. Average weight of the four friends becomes 84 Kg when Divya joins them. If Ankit is replaced by Enayat whose weight is 6 kg more than Divya, the average weight of Bholu, Chetan, Divya and Enayat becomes 83 Kg. Find the weight of Ankit.

An object travels $20$ meters in $4$ seconds and $15$ meters in the next two seconds. What is the average speed of the object?

$35$ is the average marks obtained by $120$ students. The average marks of successful candidates was $39$, and that of unsuccessful candidates was $15$. What is the number of successful candidates in that examination?

Average of three numbers $\mathrm{B}, \mathrm{C}$ and $\mathrm{D}$ is $1$ more than the average of $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$. Average of $\mathrm{A}$ and $\mathrm{D}$ is $19.5$.

Quantity $1$: Find $\mathrm{A}$.

Quantity $2$: $21$.