A bag contains 3 red marbles. The ratio of red marbles to blue marbles is 3 : 7. Find the number of blue marbles in the bag.
3:7 = red:blue
To find the number of blue marbles in the bag, we need to determine the total number of marbles in the bag.
Given that the ratio of red marbles to blue marbles is 3:7, we can find the value of the constant multiplier by adding the two parts of the ratio: 3 + 7 = 10.
Since we know that there are 3 red marbles in the bag, we can now find the total number of marbles:
3 (multiplier) = 3 (red marbles) * 10 (multiplier) = 30 marbles.
To find the number of blue marbles, we deduct the 3 red marbles from the total:
30 (total marbles) - 3 (red marbles) = 27 blue marbles.
Therefore, the bag contains 27 blue marbles.
To find the number of blue marbles in the bag, we can set up a proportion based on the given ratio.
The ratio of red marbles to blue marbles is 3 : 7, which means for every 3 red marbles, there are 7 blue marbles.
Let's represent the number of blue marbles as "x". So, we have the proportion:
3 red marbles / x blue marbles = 3 / 7
To solve for x, we can cross-multiply:
3 * 7 = 3x
21 = 3x
To isolate x, we divide both sides of the equation by 3:
21/3 = x
7 = x
Therefore, there are 7 blue marbles in the bag.