Case (i)
ATQ,
As we know, there are infinite rational numbers between any two numbers.
Therefore, there are infinite numbers of rational numbers between 5 and 7.
Case (ii)
ATQ,
Total number of children =7
Also, total number of student participants in the campaign =5
Fraction =Total number of students participatedTotal number of children=57.
Therefore, fraction of students participated in the campaign =57.
Case(iii)
Decimal expansion of 57=0.714285
Here, 0.714285 is a non terminating and recurring decimal expansion.
Therefore, decimal form of 57 i.e 0.714285 is a non terminating and recurring decimal expansion.