Given, the figure shows the relation between speed and time. So, the area of the figure will be displacement.

Therefore,

area of first triangular $\left(d_1\right)=\frac{1}{2}\times 10\times 10=50 \mathrm{m}$ , area of second triangular

$\left(d_2\right)=\frac{1}{2}\times \left(-10\right)\times 10=-50 \mathrm{m}$

Therefore, the total area $\left(d\right)=$ total displacement of the particle

$\Rightarrow d_1+d_2=50-50=0$