Hello!
Answer:

Explanation:
Let x be the number of Ahmad's marbles. So:
Ahmad =

Benny =

We also know:

Replace Benny's marbles and Ahmad's marbles by
and
.
Therefore, we have this equation:

We have just to solve this equation to find the number of Ahmad's marbles for then to find the number of Benny's marbles.
◼ Simplify both sides:

◼ Multiply both sides by 3:

◼ Simplify both sides:

◼ Simplify the fraction:

◼ Multiply both sides by 5:

◼ Simplify both sides:

◼ Subtract 3x from both sides:

◼ Simplify both sides:

◼ Divide both sides by 7:

◼ Simplify both sides:

So the number of Ahmad's marbles is 15.
To find the number of Benny's marbles, we know:
Benny =

So we have just to replace x by 15:
Benny =

So the number of Benny's marbles is 50.
Check:


So the equation
is verified if x = 15.