I think that the answer is seven but i’m not sure
Since the dice are fair and the rolling are independent, each single outcome has probability 1/15. Every time we choose

We have
and
, because the dice are fair.
Now we use the assumption of independence to claim that

Now, we simply have to count in how many ways we can obtain every possible outcome for the sum. Consider the attached table: we can see that we can obtain:
- 2 in a unique way (1+1)
- 3 in two possible ways (1+2, 2+1)
- 4 in three possible ways
- 5 in three possible ways
- 6 in three possible ways
- 7 in two possible ways
- 8 in a unique way
This implies that the probabilities of the outcomes of
are the number of possible ways divided by 15: we can obtain 2 and 8 with probability 1/15, 3 and 7 with probability 2/15, and 4, 5 and 6 with probabilities 3/15=1/5
The average cost in 1990 is <span>$12,841.</span>
<span><span> 15x2y2+3x3y+75x4</span> </span>Final result :<span> 3x2 • (25x2 + xy + 5y2)
</span>
Step by step solution :<span>Step 1 :</span><span>Equation at the end of step 1 :</span><span><span> (((15•(x2))•(y2))+((3•(x3))•y))+(3•52x4)
</span><span> Step 2 :</span></span><span>Equation at the end of step 2 :</span><span><span> (((15•(x2))•(y2))+(3x3•y))+(3•52x4)
</span><span> Step 3 :</span></span><span>Equation at the end of step 3 :</span><span> (((3•5x2) • y2) + 3x3y) + (3•52x4)
</span><span>Step 4 :</span><span>Step 5 :</span>Pulling out like terms :
<span> 5.1 </span> Pull out like factors :
<span> 75x4 + 3x3y + 15x2y2</span> = <span> 3x2 • (25x2 + xy + 5y2)</span>
Trying to factor a multi variable polynomial :
<span> 5.2 </span> Factoring <span> 25x2 + xy + 5y2</span>
Try to factor this multi-variable trinomial using trial and error<span>
</span>Factorization fails
Final result :<span> 3x2 • (25x2 + xy + 5y2)
</span><span>
</span>
4:45 because 9:45+5:30=15:15. When subtracted from so that equals 4:45