20X0.3= 6
30X0.3= 9
40X0.3= 12
Answer: 8 days
Step-by-step explanation:
6 miles has been paved already.
Number of miles left = 30 - 6
= 24 miles
If they are paving at 3 miles a day, the days they will take to finish is:
= 24/3
= 8 days
The probability of multiple events happening is found by multiplying the probabilities of each event together.

So yes, 1/10 is the answer :)
double every 6 months
in 6 months there would be 250*2 = 500 crickets
in 1 year there would be 500*2 = 1000 crickets
in 1.5 years there would be 1000 *2 = 2000 crickets
in 2 years there would be 2000 *2 = 4000 crickets