<span>Sam had to substitute 100 instead of X
</span><span>5x+3x+20 =
8x + 20 =
8*100 + 20 =
800 + 20 =
820 </span>← answer
Given a1 = 90
Common difference = adding
90 + 9 = 99, second term
99 + 9 = 108, third term
And keep doing that
You would get
90, 99, 108, 117, 126, 135
If you're rolling 5 dice, and all dice have a 1 on them, then you still have a 4/5 chance that four of the five dice will show 1.
I plugged it into my calculator and I got 1,870.