Question

Mohan finished colouring a picture in $\frac{7}{12}$ hour. Keerthi finished colouring the same picture in $\frac{3}{4}$ hour. Who worked longer? By what fraction was it longer? [3 MARKS]

Answer 1

Method I

Given that
Mohan finishes the work in $\frac{7}{12}$ of an hour.
And,Keerthi finishes the work in $\frac{3}{4}$ of an hour.

Now, $\frac{7}{12}$ of an hour
$\Rightarrow \frac{7}{12}\times 60minutes$
$\Rightarrow 35mins$
And,
$\frac{3}{4}$ of an hour
$\Rightarrow \frac{3}{4}\times 60$
$\Rightarrow 45minutes$

Clearly, Keerthi worked more by 45 - 35 = 10 more minutes.

Method II

Given: $\frac{7}{12}and\frac{3}{4}$
Making them Like fractions we have
$\frac{7\times 1}{12\times 1}\&\frac{3\times 3}{4\times 3}$
i.e. $\frac{7}{12}<\frac{9}{12}$

Clearly, Keerthi who takes ${\frac{3}{4}}^{th}$ of an hour takes longer than Mohan who takes ${\frac{7}{12}}^{th}$ of an hour.
So, subtracting we have
$\frac{9}{12}-\frac{7}{12}=\frac{2}{12}=\frac{1}{6}$ of an hour more.