Question 32895
A+B=50 & .1A+.6B=50*.3 OR A=50-B SUBSTITUTING IN EQUATION #2 WE GET

.1(50-B)+.6B=15 OR 5-.1B+.6B=15 OR .5B=10 OR B=20 THEREFORE A=50-B OR A=30

PROOF .1*30+.6*20=50*.3 OR 3+12=15 OR 15=15