@ august
first calculate the volume .
if u will calculate the volume u will get it as 500 cc ..
after that find the total no.of K+ ions.
then calculate by the following formula
volume*molarity*n factor
and acc to the question by calculating
u will get it as
K+ = 250*0.2*1 + 250*0.2*2 = 150
the molarity will be 0.2 in each case here ..
then for finding the final answer apply the following formula
conc of K+ = no.of K+/volume
by applying the above formula u will get
150/500 = 0.3M
which will be the answer
HOPE U WILL GET HOW TO SOLVE SUCH QUESTIONS
ALL THE BEST
IF MORE DOUBT THEN ASK .
