The velocity time graphs of a car and a scooter are shown in the...

Distance travelled by car in $15s$ $= \dfrac{1}{2} \times 45 \times 15 \times = \dfrac{675}{2}m$. Distance travelled by scooter in $15s$$= 30 \times 15 = 450$. Let car catches scooter in time $t$
difference between the distance travelled by car and scooter in $15s$ in$\text{⇒}450 - \dfrac{675}{2} = 112.5m$
$⇒ \dfrac{675}{2} + 45\left(t - 15\right) = 30t$
$337.5 + 45t - 675 = 30t ⇒ 15t = 337.5$
$⇒ t = 22.5s$.