Arihant Expert Team Solutions for Exercise 1: Practice Questions

A motorist travels to a place $150 km$ away at an average speed of $50 km/h$ and returns at $30 km/h$. His average speed for the whole journey (in $km/h$) is:

Three years ago, the average age of a family of five members was $17$ $\mathrm{years}.$ A baby having been born, the average age of the family is the same today. The present age of the baby is:

Five years ago, the average age of $P$ and $Q$ was $15 \mathrm{years}.$ The average age of $P,Q$ and $R$ today is $20 \mathrm{years}.$ How old will $R$ be after $10 \mathrm{years}$?

The average of $11$ observations is $60$. If the average of the first five observations is $58$and that of the last five is $56$, then the sixth observation is:

A cricketer has completed $14$ innings and his average is $30$ runs. How many runs must he make in his next innings so as to raise his average to $32$ runs?

The average of five numbers is $42$, while the average of another eight numbers is $81$. What is the combined average of all numbers together?

The average of the first five multiples of $3$ is:

Find the average of four numbers $2\frac{3}{4}, 5\frac{1}{3}, 4\frac{1}{6}, 8\frac{1}{2}$.