Find the missing number in the series.20, 35, 60, 105, 190, _____

Let's find the differences between the consecutive numbers:$35-20=15$$60-35=25$$105-60=45$$190-105=85$ Now, find the difference between these differences (double difference):$25-15=10$$45-25=20$$85-45=40$ The double differences follow a pattern of multiplying by 2 ($10\times 2=20$, $20\times 2=40$).The next double difference should be $40\times 2=80$.Therefore, the next single difference will be $85+80=165$.The missing number in the series is $190+165=355$.