the ratio of red marbles to blue marbles in a bag 3:4 if there are 42 marbles in the bag. how many of the marbles are red

total number of red marbles=18 marbles

Step-by-step explanation:

Step 1

Express the fraction of each type of marble as a function of the total number of marbles as shown;

Let;

total marbles=x

red marbles=3 / (3+4) = 3/7x

blue marbles=4/7 x

But x=42 marbles

The total number of marbles for each type can be expressed as;

total number of red marbles=fraction of red marbles*total number of marbles

where;

fraction of red marbles=3/7 x

total number of marbles=42

replacing;

total number of red marbles = (3/7) * 42=18 marbles

total number of blue marbles=fraction of blue marbles*total number of marbles

where;

fraction of blue marbles=4/7 x

total number of marbles=42

replacing;

total number of blue marbles = (4/7) * 42=24 marbles