The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400 g. The weight of the teacher is

Answer: Option C

Explanation:

Total weight increased is 1.5 * 10 = 15.
So weight of new person is 45+15 = 60

Answer: Option B

Explanation:

X =((3y+3z)/6)
or
2X= y + z

Answer: Option C

Answer: Option B

Explanation:

\begin{aligned}
( \frac {65+67+76+82+85}{5} ) = 75
\end{aligned}

Answer: Option B

Explanation:

Average speed will be

\begin{aligned}

\frac{2xy}{x+y} km/hr


= \frac{2(50)(30)}{50+30} km/hr
\end{aligned}

= 37.5 km/hr