Answer :
Final answer:
To ensure Mrs. Grey buys the same total length of each color ribbon, she must find the least common multiple of the roll lengths. She should purchase 4 rolls of blue, 5 rolls of silver, and 3 rolls of yellow ribbon, as the LCM of the roll lengths is 60 meters.
Explanation:
The question involves finding the least number of rolls of blue, silver, and yellow ribbon that Mrs. Grey must buy so she has the same length of each color. The blue ribbon comes in 15-meter rolls, the silver ribbon in 12-meter rolls, and the yellow ribbon in 20-meter rolls. To solve this, we need to find the least common multiple (LCM) of the lengths of the rolls, which is the smallest number that is a multiple of each of the given numbers. The LCM of 15, 12, and 20 is 60.
This means Mrs. Grey needs to purchase 4 rolls of blue ribbon (60/15), 5 rolls of silver ribbon (60/12), and 3 rolls of yellow ribbon (60/20) to ensure that she buys the same total length of each color. This calculation ensures the most efficient and equal use of each ribbon type.