Arrange the fractions $\frac{21}{50},\frac{17}{50},\frac{43}{50}$ in an increasing order.

The given fractions are $\frac{21}{50},\frac{17}{50},\frac{43}{50}$.

Here, the denominators are the same in each fraction i.e., the given fractions are like fractions.

If two or more fractions have the same denominator, then the fraction having the greatest numerator is the largest fraction.

Comparing the numerators of the given fractions:

17 < 21 < 43

Hence, the given fraction can be arranged in the increasing order as $\frac{17}{50}<\frac{21}{50}<\frac{43}{50}$