Question 212323
XY/(X+Y)=30
45Y/(45+Y)=30
45Y=30(45+Y)
45Y=1,350+30Y
45Y-30Y=1,350
15Y=1,350
Y=1,350/15
Y=90 MINUTES FOR THE SECOND PIPELINE TO FILL THE TANK WORKING ALONE.
PROOF:
45*90/(45+90)=30
4,050/135=30
30=30