“I could not do it, sir.”
“How many marbles can you buy for a penny?”
“Twelve new ones, sir.”
“And how many for two pence?”
“Twenty-four.”
“And how many for a half-penny?”
“Six.”
“If you were to have a penny a day, what would that make in a week?”
“Seven pence.”
“But if you paid two pence out of that, what would you have left?”