Answer:
The number of red marbles in the bag = 40
Explanation:
Here, given: The number of blue marbles in the bag = 60
Let us assume , The number of red marbles in the bag = m
So, the total marbles = Red + Blue = 60 + m
Also given ratio of blue marbles : total marbles = 3 : 5
⇒ 3:5 = 60 : 60+ m
By the RATIO OF PROPORTION:

Hence the number of red marbles in the bag = 40