Let x and y be the two numbers. Then by assumptions we have x+y=30 and x-y=20. Hence, y=x-20 and by plugging this into the first equation we obtain x+x-20=30 or 2x=50 or x=25 and y=5
Step-by-step explanation:
So, divide 30 by 2 . That gives you 15 for x, 15 for y. Now, you have difference of six, divide by two, that equals 3.
Since Density = mass/ volume (d = m / v), and assuming the 15 fish weigh 1 gram each - if weight of each fish isn't given - (making that a total of 15 grams),