Andrew is searching for a cup and discovers that he has 20 plates for every 5 pairs of cups. If he has 40 plates how many pairs of cups does he have?
So, the amounts are in the ratio 5:20 = 1:4
Now it's just like the earlier problem. Use their sum.
To find out how many pairs of cups Andrew has, we can use the given information that he has 20 plates for every 5 pairs of cups.
Let's calculate the ratio of plates to pairs of cups: 20 plates / 5 pairs of cups = 4 plates per pair of cups.
If Andrew has 40 plates, we can divide that by the ratio to find the number of pairs of cups: 40 plates / 4 plates per pair = 10 pairs of cups.
Therefore, Andrew has 10 pairs of cups.