Two cubes and one pyramid weigh 9 lb. Seven cubes and two pyramids weigh 24 lb. All cubes weigh the same, and all pyramids weigh the same. What is the weight of one pyramid?
Answer: 5 lb
Explanation: Let x be the weight of a cube. Let y be the weight of a pyramid.
The first sentence becomes: 2x + y = 9.
The second sentence is: 7x + 2y = 24.
Solve this as a system of equations by any method you choose… substitution, elimination, Cramer’s Rule, etc. Or use my TI-84 Plus program ‘CRAMER’.
x = 2, y = 5
‘y’ is the weight of one pyramid, so the answer is 5.