The triangles PTQ and RTS are similar; so the ratios of corresponding sides are equal.
Let us denote the unknown length SQ as x.
We could make the following similarity relation;

Cross multiply to obtain;

Therefore;

Therefore, the answer is option A
<h3>
Answer: (m+n)/(mn)</h3>
Work Shown:
Josh:
1 room = m hours
1/m room = 1 hour
Kevin:
1 room = n hours
1/n room = 1 hour
We see that the rates for Josh and Kevin are 1/m and 1/n respectively. This is the amount of a room they paint in one hour. Combine the fractions
1/m + 1/n = n/(mn) + m/(mn) = (n+m)/(mn) = (m+n)/(mn)
The expression (m+n)/(mn) represents how much of the room they get painted in 1 hour. This is if they work together and it assumes neither worker slows the other one down.
284 x $1.39= $394.76
He made $394.76 washing 284 windows last week
3+(-4)=(-1)
so, 3 is the missing number