Mandy knows that a 5 meter long metal bar has a mass of 40 kg. Mandy wants to figure out the mass (w) of a bar made out of the same metal that is 3 meters king and the same thickness.

24 kg

Step-by-step explanation:

Step 1. Write the proportion

5:40 = 3:x

Step 2. Multiply means (40 & 3) and then the extremes (5 & x)

5x = 120

Step 3. Divide both sides by 5 to find x

5x = 120

5 5

x = 24

alternative way,

Divide 5 by 40 to get its ratio, then divide 3 by the quotient we get earlier.

5/40 = 0.125

3/0.125 = 24

w = 24

Step-by-step explanation:

If a 5 meter long metal bar has a mass of 40kg, this means a 1 meter long metal bar has a mass of 8kg because 40kg/5m = 8. So, 1 meter long metal bar is 8kg. This means a 3 meter long metal bar has a mass of 24kg because 8 * 3 = 24.