Let the mass of Marc be denoted by $x$ kg.

• James is 3 kg heavier than Marc, so his mass is $x + 3$ kg.
• Ben is three times heavier than Marc, so his mass is $3x$ kg.

The total mass of the three boys is given as 118 kg, so we can write the equation:

$x + (x + 3) + 3x = 118$

Simplify the equation:

$x + x + 3 + 3x = 118$

$5x + 3 = 118$

Subtract 3 from both sides:

$5x = 115$

Now, divide by 5:

$x = 23$

So, Marc’s mass is 23 kg. Ben’s mass is three times Marc’s mass:

$\text{Ben's mass} = 3 \times 23 = 69 \, \text{kg}$

Thus, Ben's mass is 69 kg.

Do you want more details or have any questions?

Here are 5 related questions:

1. What is James's mass based on this information?
2. How would the total mass change if Ben was twice as heavy as Marc?
3. If Marc gained 5 kg, what would the new total mass be?
4. What would the equation look like if James was twice Marc's mass?
5. How can this method be used to solve a similar problem involving four boys?

Tip: When solving word problems, start by defining variables for the unknowns. This helps set up the equations easily!