SOLUTION: Object A is 5kg heavier than the Object B and the mass of Object C is twice the mass of Object A. If the total mass of the three objects is 255kg, find the mass of Object C.

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Question 1120619: Object A is 5kg heavier than the Object B and the mass of Object C is twice the mass of Object A. If the total mass of the three objects is 255kg, find the mass of Object C.
Found 2 solutions by Theo, josgarithmetic:
Answer by Theo(13342) (Show Source):
You can put this solution on YOUR website!
x = mass of object A
y = mass of object B
z = mass of object C

object A is 5 kg heavier than object B

x = y + 5

object C is twice the mass of object A

z = 2 * x

total mass is 255 kg.

x + y + z = 255

x = y + 5 leads to y = x - 5 as follows:
start with x = y + 5
subtract 5 from both sides to get x - 5 = y

replace y with x - 5 and replace z with 2 * x in the equation of x + y + z = 255.

you will get x + x - 5 + 2 * x = 255

combine like terms to get 4 * x - 5 = 255

add 5 to both sides to get 4 * x = 260

divide both sides by 4 to get x = 65

x = 65
y = x - 5 = 60
z = 2 * x = 130

x + y + z = 255 becomes 65 + 60 + 130 = 255 which becomes 255 = 255 which is true.

x = y + 5 becomes 65 = 60 + 5 which becomes 65 = 65 which is true.

z = 2 * x becomes 130 = 2 * 65 which becomes 230 = 230 which is true.

solution is confirmed to be true.

solution is the mass of object C = z which is equal to 130.

Answer by josgarithmetic(39618) (Show Source):
You can put this solution on YOUR website!

Let b equal mass of object B.

OBJECT MASS A b+5 B b C 2(b+5) TOTAL 255

Solve for b in Total equation and evaluate C.

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