You would get 50 coins in that time.
To find this, we first need to find the unit rate. We can get that by dividing the amount of coins by the amount of time.
15 coins/ 30 mins = .5 coins per minute.
Now, we have 100 minutes in the second part of the problem, so we multiply the rate by that amount of time.
.5 coins per min * 100 mins = 50 coins