Video Transcript
Fred paid fifty dollars for a
new jumper. He then found that his friend
Ted had bought exactly the same type of jumper, but he paid sixty-five dollars
for it. Ted said he paid thirty percent
more than Fred, but Fred said he paid only twenty-three percent less than
Ted. Who was right?
First let’s look at how much
more Ted paid than Fred paid. So Fred paid fifty dollars; Ted
paid sixty-five dollars. That means compared to Fred,
Ted paid fifteen dollars more. So when Ted is comparing
himself to Fred, the starting point is fifty dollars. So we paid fifteen dollars more
than fifty dollars. And to convert that proportion
to a percentage, we need to multiply by a hundred. So that’s an increase of thirty
percent.
And Ted said that he paid
thirty percent more than Fred. Yeah well that is correct. But when Fred said that he paid
twenty-three percent less than Ted, he was comparing himself with a starting
point of Ted’s price, which was sixty-five dollars. So the difference in price is
still fifteen dollars. Fred paid fifteen dollars less
than Ted.
But when we’re working out the
proportion, that fifteen dollars is being compared to the sixty-five dollars
starting point of what Ted paid for the jumper. And again we multiply it by a
hundred to convert that to a percentage. And that is minus twenty-three
point O seven six nine two three and then lots of other digits percent. Well to the nearest one
percent, Fred did in fact pay twenty-three percent less than Ted. So it looks like he was right
too. So to answer the question “who
was right?” they were both right.
