The Malefic Milkman bought 14 kg of powdered milk for £35.00. He wanted to sell it at the standard rate for milk, but that would only have gotten him a profit of £42. He wanted to get a profit of £78. He could secretly add dark matter to the milk to increase its mass. Dark matter only costs £1.00 per kilogram.
How many kilograms of dark matter could the Malefic Milkman add to the milk to get a profit of £78?