Question

There are 50 cards in a pack and each card is either red or black

the ratio of the number of red cards to the number of black cards 1:1

10 black cards are removed from the pack

find the ratio of the number of red cards in the pack to the number of black cards in the pack
Give your answer in its simplest form


Please show your working out

Answer 1

A ratio of 1:1 means there are the same number of red and black cards, so 25 of each. Take 10 black away and now there are still 25 red but only 15 black. The ratio is 25:15, which simplifies to 5:3 ( divide 25 and 15 by 5 because 5 is the greatest common factor of 25 and 15)

Answer 2

Explanation:

Ratio Red to Black is 1:1

Therefore, Red and Black has 25 cards respectively

If 10B cards are removed, then 25-10=15B cards left

Current ratio Red to Black is 25:15 and simplest form is 5:3