Nayamat bought $\dfrac{2}{5}$ metre of ribbon and Amanat bought $\dfrac{3}{4}$ metre of ribbon. What is the total length of the ribbon they bought?

Length of ribbon bought by Nayamat = $\dfrac{2}{5}$ metre.

Length of ribbon bought by Amanat = $\dfrac{3}{4}$ metre.

Total length of ribbon = $\dfrac{2}{5} + \dfrac{3}{4}$

LCM of 5 and 4 = 20.

$\Rightarrow \dfrac{2 \times 4}{5 \times 4} + \dfrac{3 \times 5}{4 \times 5}\\[1em] \Rightarrow \dfrac{8}{20} + \dfrac{15}{20}\\[1em] \Rightarrow \dfrac{8 + 15}{20}\\[1em] \Rightarrow \dfrac{23}{20}\\[1em] \Rightarrow 1\dfrac{3}{20} \text{ metre}$

Hence, the total length of ribbon they bought = $1\dfrac{3}{20}$ metre.